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Ohm’s Law: The Definitive Guide | Theory, Formulas (V=I.R), and 5 Real-World Applications

Electronic Circuits — Sat, 29 Nov 2025 18:20:21 +0000

Ohm's Law: Relationship between voltage, current and resistance in electrical circuits.

🌐 You can read this article in: Português | Español

Master the fundamental principles of electricity and become an expert in circuit projects!

🔌 Did you know? Ohm's Law is one of the most important concepts in electricity and is present in virtually all electronic devices we use daily, from your smartphone to complex electrical systems.

📜 The History Behind the Law: Who was Georg Ohm?

Born in Erlangen, Germany, in 1789 (and not in 1879 as sometimes cited), Georg Simon Ohm was a brilliant physicist and mathematician whose curiosity led him to decipher one of the greatest mysteries of his time: the relationship between electrical quantities. At a time when electricity was almost magic, Ohm brought clarity and mathematics to the field.

His contribution was so monumental that the unit of electrical resistance, the Ohm (Ω), was named in his honor. Thanks to him, today we can predict, control and design circuits with incredible precision. Shall we discover his legacy together?

🧐 What is Ohm's First Law? The Simplified Concept

In essence, Ohm's First Law is the golden rule of electricity. It describes in a simple and elegant way how the three main quantities of an electrical circuit are related: Voltage, Current and Resistance.

Imagine that the law establishes an agreement between these three elements. The magical formula that expresses this relationship is:

  V = R × I

Where each letter represents:

V: Voltage or Potential Difference. It is the "force" that drives electrons, measured in Volts (V). Think of it as the water pressure in a faucet.

R: Resistance. It is the opposition that the material offers to the flow of current. It is measured in Ohms (Ω). It would be like the "narrowness" of the pipe.

I: Electric Current. It is the flow of electrons that passes through the circuit. It is measured in Amperes (A). It is equivalent to the amount of water flowing through the pipe.

The law states that, for a resistor with constant resistance, the current (I) is directly proportional to the voltage (V) applied. Doubling the voltage, you double the current. It's that simple! If you know two of these values, you can easily calculate the third.

🔑 The Best Analogy: Understanding Ohm's Law with Water

To fix this concept, nothing better than a practical analogy. Think of a simple water system:

Fig. 2 - Hydraulic Analogy to visualize Voltage, Current and Resistance.

Voltage (V) is the pressure that the water exerts in the tank. More height in the tank means more pressure.

Current (I) is the flow of water that passes through the system per second.

Resistance (R) is the water wheel that consumes part of the energy of the flow. A wheel with more blades or larger diameter offers more resistance to the water flow.

If you increase the water pressure (increase the Voltage), more water will flow through the system (increase the Current), making the wheel spin faster. If you maintain the pressure but increase the resistance of the wheel (more blades or larger diameter), the water flow will decrease (the Current will decrease). It's exactly how Ohm's Law works!

🧪 The Three Essential Formulas of Ohm's Law

Knowing the main formula V = R × I is great, but in practice, you'll need to calculate each of the quantities. To facilitate this, we can rearrange the equation. And to memorize, nothing better than the famous Ohm's Law Triangle.

Fig. 3 - Ohm's Law Triangle: Practical calculation guide

The magic happens here: cover the letter representing the Voltage (V), Resistance (R), or Current (I) you want to find in the triangle, and the position of the other two will show you the formula to use.

1️⃣ To calculate Voltage (V)

Cover the 'V' in the triangle. The 'R' and 'I' remain side by side, indicating a multiplication.

  V = R × I

2️⃣ To calculate Current (I)

Cover the 'I'. The 'V' remains over the 'R', indicating a division.

  I = V ÷ R

3️⃣ To calculate Resistance (R)

Cover the 'R'. The 'V' remains over the 'I', also indicating a division.

  R = V ÷ I

With these three formulas at the tip of your tongue (or at your fingertips), you're ready to solve most basic electrical circuit problems!

🪛 Practical Examples: Applications of Ohm's Law in Circuits

Theory is fundamental, but practice is what solidifies knowledge. Ohm's Law is applied in countless everyday situations of an engineer, from sizing simple components to analyzing complex systems. Below, we present five practical examples that demonstrate the direct and precise application of this law in real scenarios.

🔌 Example 1 (Circuit): In a simple circuit, we have a 10 Volt source connected to a 500 Ω resistor. What is the electric current that flows through the circuit?

Fig. 4 - Simple circuit to apply Ohm's Law calculation.

1️⃣ Step: Identify what you need to find.

The problem asks for the electric current (I).

2️⃣ Step: Identify the data you already have.

Voltage (V) = 10 V
Resistance (R) = 500 Ω

3️⃣ Step: Choose the correct formula.

To find the current (I), we use the formula: I = V ÷ R

4️⃣ Step: Substitute the values and calculate.

  I = 10 V ÷ 500 Ω

  I = 0.02 A 

To make it easier to read, we can convert Amperes (A) to milliamperes (mA), knowing that 1 A = 1000 mA.

  I = 0.02 × 1000 = 20 mA

Done! A current of 20 milliamperes flows through the circuit. See how simple it is?

🔴 Example 2 (LED): You want to connect an LED to a 5V source. The LED datasheet specifies a forward voltage (V_f) of 2.1V and an ideal operating current (I_f) of 20mA. What should be the value of the series resistor to ensure safe and efficient operation of the component?

1️⃣ Step: Identify what you need to find.

The problem asks for the value of the resistor (R).

2️⃣ Step: Identify the data you already have.

Source voltage (V_source) = 5 V
LED voltage (V_f) = 2.1 V
LED current (I_f) = 20 mA = 0.02 A

3️⃣ Step: Choose the correct formula.

First, we need to calculate the voltage that the resistor needs to "absorb": V_R = V_source - V_f. Then, we apply Ohm's Law to find R: R = V_R ÷ I_f

4️⃣ Step: Substitute the values and calculate.

V_R = 5V - 2.1V = 2.9V
R = V_R ÷ I_f = 2.9V ÷ 0.02A = 145 Ω → 150Ω (commercial value)

💡 Practical tip: Always choose the closest commercial value above the calculated one to ensure the LED lasts longer!

🏭 Example 3 (Automation): You are installing a sensor in a 24V DC industrial automation system, located 50 meters away from the source and consumes 100mA. The wiring used is a 1.5 mm² copper cable, with a resistance of approximately (0.0124 Ω/m). What is the voltage that actually reaches the sensor, considering the voltage drop in the round-trip cable?

1️⃣ Step: Identify what you need to find.

The problem asks for the voltage that reaches the sensor (V_sensor).

2️⃣ Step: Identify the data you already have.

Source voltage (V_source) = 24 V
Sensor current (I) = 100 mA = 0.1 A
Cable resistance per meter = 0.0124 Ω/m
Cable length = 50 m (go) + 50 m (return) = 100 m

3️⃣ Step: Choose the correct formula.

First, we calculate the total resistance of the cable (R_total). Then, we use Ohm's Law to find the voltage drop (V_drop) in this cable: V_drop = I × R_total. Finally, we subtract this drop from the source voltage: V_sensor = V_source - V_drop

4️⃣ Step: Substitute the values and calculate.

  Rtotal = 100m × 0.0124 Ω/m = 1.24 Ω

  Vdrop = I × Rtotal = 0.1A × 1.24Ω = 0.124V

  Vsensor = Vsource - Vdrop = 24V - 0.12V =
  23.876V

The voltage drop is minimal, but this calculation is crucial for higher power systems or low voltage signals, where this loss can be critical.

💡 Important alert: In real systems, drops above 5% (1.2V in 24V) can cause failures. Always calculate the voltage drop over long distances!

🤖 Example 4 (Logic Level Compatibility): You need to connect the digital output of an Arduino or PLC that operates with 5V logic to an input pin of an ESP32, which accepts a maximum of 3.3V. To protect the ESP32, you decide to use a voltage divider to reduce the signal. The divider is formed by R₁ (connected to the 5V signal) and R₂ (connected to GND). If you set R₂ to 10 kΩ, what should be the value of R₁?

1️⃣ Step: Identify what you need to find.

The problem asks for the value of the resistor R₁.

2️⃣ Step: Identify the data you already have.

Input voltage (V_in) = 5 V
Output voltage (V_out) = 3.3 V
Resistor R₂ = 10 kΩ

3️⃣ Step: Choose the correct formula.

The voltage divider formula is: V_out = V_in × (R₂ / (R₁ + R₂)). We need to isolate R₁ in this equation.

4️⃣ Step 4: Substitute the values and calculate.

3.3V = 5V × (10kΩ / (R₁ + 10kΩ))
3.3 / 5 = 10kΩ / (R₁ + 10kΩ)
0.66 × (R₁ + 10kΩ) = 10kΩ
0.66 × R₁ + 6.6kΩ = 10kΩ
0.66 × R₁ = 3.4kΩ
R₁ = 3.4kΩ / 0.66 ≈ 5.15 kΩ → 5.1kΩ (commercial value)

💡 Teacher's Note: This voltage divider method is a simple and effective solution for unidirectional and low speed signals (e.g., activating an input pin). For bidirectional communication (like I2C) or high-speed (SPI, UART), the professionally correct approach is to use a logic level converter module. It's safer, more robust, and guarantees data integrity.

🔋 Example 5 (Battery): You tested a battery: without load, the voltage at its terminals is 12.6V, but when connecting a load of 2A, the voltage at the terminals drops to 12.1V. What is the internal resistance (R_int) of the battery?

1️⃣ Step: Identify what you need to find.

The problem asks for the internal resistance of the battery (R_int).

2️⃣ Step: Identify the data you already have.

No-load voltage (V_{no load}) = 12.6 V
Load voltage (V_{with load}) = 12.1 V
Load current (I) = 2 A

3️⃣ Step: Choose the correct formula.

The voltage drop in the battery is caused by its own internal resistance. This drop (ΔV) is proportional to the current that passes through it, according to Ohm's Law: ΔV = I × R_int, where ΔV = V_{no load} - V_{with load}.

4️⃣ Step: Substitute the values and calculate.

  ΔV = Vno load - Vwith load = 12.6V - 12.1V = 0.5V

  Rint = ΔV / I = 0.5V / 2A = 0.25 Ω

💡 Teacher's tip: Batteries with internal resistance above 0.5Ω are worn out and don't deliver enough power for starting or heavy loads.

🤔 Frequently Asked Questions (FAQ)

To ensure your project is a success, we've compiled some of the most common questions about Ohm's Law. Check them out!

Does Ohm's Law apply to all electronic components? 🔽

Varistor Explained: How It Works and Where to Use It

Electronic Circuits — Thu, 27 Nov 2025 21:03:16 +0000

Varistors: Essential components for electronic circuit protection

🌐 You can read this article in: Português | Español

Hello, electronics enthusiasts!

If you've ever wondered how your electronic devices survive voltage spikes, the answer may lie in a small component called a Varistor. In this complete guide, we'll explore everything about these silent protectors that save our devices daily.

A Varistor is a variable resistor whose resistance depends on the applied voltage. The name is a linguistic amalgam of two words: "Variable" and "Resistor". These components are true guardians of electronic circuits, acting as shields against overvoltages that could permanently damage sensitive equipment.

They are also known by the names:

VDR (Voltage Dependent Resistor) - Voltage Dependent Resistor
MOV (Metal Oxide Varistor) - Metal Oxide Varistor

Unlike conventional resistors, varistors have non-ohmic characteristics and are classified as non-linear resistors. This unique characteristic makes them indispensable in protection applications.

🧐 How Varistors Work: The Protection Mechanism

To understand how a varistor works, imagine an intelligent traffic guard that only allows cars (electric current) to pass when the speed (voltage) exceeds a safe limit. Similarly, a varistor remains with high resistance (practically insulating) under normal operating conditions, but its resistance drops drastically when the voltage reaches a specific threshold value.

Unlike potentiometers and rheostats, where the resistance changes gradually from a minimum to a maximum value, the operation of a Varistor is more abrupt: when subjected to a certain voltage (threshold voltage), the differential resistance suddenly drops to a very low value.

Varistors are composed of semiconductor elements that provide overvoltage protection in a circuit. Their functionality is similar to a Zener diode, allowing voltages below the limit to pass unchanged, but diverting excess energy when the voltage exceeds the safe value.

In practice, the main function of the Varistor is to protect against excessive transient voltages in the circuit. These transient voltages are usually caused by electrostatic discharges, lightning surges, or switching of inductive loads, phenomena that we will detail later.

🔧 Types of Varistors: Know the Variations

There are several types of varistors, each with specific characteristics for different applications. Let's explore the main types:

1️⃣ Zinc Oxide Varistor (MOV)

The zinc oxide varistor is the most common type of varistor. It is composed of a zinc oxide ceramic material that has high resistance under normal conditions, but its resistance decreases significantly when a surge voltage is applied.

Zinc oxide varistors are widely used for surge protection in electronic equipment and power systems. Their popularity is due to the excellent cost-benefit ratio and efficiency in protecting against a wide range of overvoltages.

2️⃣ Zinc Oxide Varistor with Bismuth

This is a variation of the traditional zinc oxide varistor that contains a small amount of bismuth in its composition. This addition aims to improve the electrical and performance characteristics of the varistor.

Bismuth is added to zinc oxide to promote the formation of a more stable and uniform semiconductor grain boundary layer, resulting in a varistor with improved electrical characteristics.

🔽 The main advantages of the zinc oxide varistor with bismuth addition include:

Lower breakdown voltage: Bismuth reduces the breakdown voltage of the varistor, allowing it to start conducting at a lower voltage compared to the conventional zinc oxide varistor.
More stable temperature coefficient: The addition of bismuth helps to stabilize the temperature coefficient of the varistor, making it less sensitive to temperature variations.
Better performance at high temperatures: The zinc oxide varistor with bismuth addition has better thermal resistance, allowing it to maintain its performance even in high temperature conditions.

3️⃣ Metal Oxide Varistor (MO)

The metal oxide varistor uses a metal oxide instead of zinc oxide. It offers surge response characteristics similar to zinc oxide varistors, but with faster response properties and greater energy absorption capacity.

These varistors are often found in high-power applications and industrial voltage surge protection systems, where fast response is crucial.

4️⃣ Silicon Carbide Varistor (SiC)

The silicon carbide varistor is used for high voltage and high power applications. It has a fast response to voltage surges and is capable of handling high energy levels.

Silicon carbide varistors are often found in power systems, power transmission, and other high-power applications, where energy dissipation capability is a critical factor.

💡How Voltage Change Affects the Varistor's Resistance?

This characteristic is determined by the semiconductor composition of the varistor. When manufactured with semiconductor material, its intrinsic characteristics cause the Varistor to change its resistance with high operating voltages.

When the voltage applied to a Varistor is greater than its nominal value (threshold voltage), the effective resistance of the Varistor drops drastically and continues to decrease as the applied voltage increases.

The curve representing the static resistance of the Varistor in relation to its applied voltage is shown in Figure 2 below:

Fig. 2 - Characteristic resistance curve Varistor - Threshold voltage

🔌 Varistor Symbol

In circuit diagrams, varistors are represented by specific symbols that differentiate them from other components. Knowing these symbols is essential to correctly identify varistors in electrical schematics.

Fig. 3 - Varistor: Symbols and Standards

👉 How Does a Varistor Help Suppress Voltage Transients?

To understand this, let's first identify the sources of transient voltage. The origin of these transients in electrical circuits is independent of whether they operate from an AC or DC source, and can come from the circuit itself or from external sources.

These transients result in an increase in voltage to several thousand volts, which can be catastrophic for the circuit. Imagine a small river that suddenly turns into a devastating flood - that's how voltage transients can affect a delicate electronic circuit.

The varistor acts as an intelligent containment system, detecting the abnormal voltage increase and providing a low resistance path to divert the excess energy, thus protecting the most sensitive components of the circuit.

📊 Voltage-Current (V-I) Characteristics

According to Ohm's law, the current-voltage characteristic curve of a resistor is a straight line, assuming the resistor value is kept constant. In this case, the current flowing through a resistor is directly proportional to the applied voltage.

However, in the case of a Varistor, the current-voltage characteristic curve is not a straight line. This is due to the unusual resistance behavior of the Varistor, where a small change in the applied voltage can cause a significant change in the current flowing through it.

The voltage-current characteristic curve of a Varistor is shown in Figure 4 below:

Fig. 4 - Current/Voltage Characteristic Curve of a Varistor

The characteristic current-voltage curve of a Varistor shows a linear relationship between current and voltage when the Varistor is not conducting. This occurs because the current flowing through the Varistor will remain constant and the value is very low - this is called the leakage current, generally on the order of a few milliamperes.

This small current will remain constant until the voltage applied across the Varistor reaches its nominal voltage, also called the clamping voltage. The nominal voltage of a Varistor is the voltage across it, measured with a specified DC current of 1mA.

When the applied voltage of the Varistor reaches its nominal voltage, the behavior of the Varistor changes from the insulation state to the conduction state. The resistance of the Varistor becomes very small when the applied transient voltage is greater than or equal to the nominal voltage of the Varistor.

This occurs due to a phenomenon called avalanche breakdown in semiconductor materials, a form of current multiplication that allows large currents in materials that previously acted as insulators. Due to this situation, the small leakage current increases rapidly.

Even though the current flowing through the Varistor increases, the voltage across it is limited to a value close to the nominal voltage. This means that the Varistor acts as a self-regulator for the transient voltages applied across it, allowing more current to flow through the Varistor.

Thus, after crossing the nominal voltage of the Varistor, the current-voltage curve becomes a steep non-linear curve. Due to this characteristic, a Varistor can pass currents varying extensively over a very narrow range of voltages, cutting off any voltage spikes.

🛡️ Practical Applications of Varistors

Now that we understand how varistors work, let's explore where they are used in the real world:

Power supplies: Protect against voltage spikes in the power grid
Surge protectors: In power strips and voltage stabilizers
Telecommunications equipment: Protect telephone and data lines
Industrial systems: In control panels and automation
Home appliances: In TVs, computers, and other sensitive devices
Power systems: In transformers and substations

⚠️ How to Select the Appropriate Varistor

To select the correct varistor for your application, consider the following factors:

Nominal voltage: Must be higher than the maximum normal operating voltage of the circuit
Energy absorption capacity: Determines how much energy the varistor can dissipate during a surge
Maximum surge current: The maximum current that the varistor can withstand without damage
Response time: How quickly the varistor responds to a voltage spike
Physical size: Must be compatible with the available space in the project

🔗 Related Content

If you liked this project, you might also be interested in these other articles:

🧾Conclusion: The Invisible Guardian of Electronic Circuits

Varistors are essential electronic components for protecting equipment against voltage surges. They function as a kind of "relief valve" for excessive electrical current, dissipating it safely and protecting the connected devices.

Furthermore, varistors are widely used in various applications, from telecommunications equipment to renewable energy systems. Understanding the functioning and importance of varistors is fundamental to ensure the safety and efficiency of electronic equipment in our daily lives.

When designing or repairing electronic circuits, never underestimate the importance of including appropriate varistors for overvoltage protection. They may seem like simple components, but they are true anonymous heroes that save valuable equipment from irreparable damage.

🤔 Frequently Asked Questions (FAQ)

To ensure your project is a success, we've compiled some of the most common questions about varistors. Check it out!

What is the difference between a varistor and a Zener diode? 🔽

Arduino Lesson 9 – LED Sequencing with Arrays (Practical Guide)

Electronic Circuits — Sun, 07 Nov 2021 00:08:00 +0000

Arduino: Lesson 9 – LED Sequencing using Array Data Structure

Welcome to Lesson 9 – Basic Arduino Course

In today’s lesson, we will learn how to use 5 LEDs connected to 5 Arduino ports, which will light up in sequence and right after the cycle ends, will go out in sequence. With that, we will learn a new instruction, the Array data structure.

What is Array?

An array is a collection of variables that are accessed with an index number. However, the “array” data structure is not exactly an existing data type.

There are arrays of variables like “char“, “int“, “boolean“, “float” and so on. This means that an array can be variables of any type mentioned above.

An array, orvector, for example, is a collection of variables of a specific type, which may even use the same nomenclature, but which will be distinguished by an indexed number.

For example: We can use a variable type “float” with a single name indexed by number, instead of different variables (VarFloat_1, VarFloat_2, VarFloat_3…) we can use a single grouped array with the same nomenclature that will allow each variable be manipulated separately by a numerical index, (VarFloat [0], VarFloat [1], VarFloat [2] …).

Hardware Required

Arduino Board
5 – LEDs
5 – 250 ohms resistor – (brown, green, brown, gold)
Jumper Wires
Protoboard (optional)

The Circuit Connections

The circuit is a bit simple, we connect the longer “Anode” legs of the 5 LEDs to the positive 5V of the Arduino, and the other shorter leg “Cathode“, we connect to the 150 ohm resistor and in series with GND, negative of the Arduino, as shown in Figure 2 below.

Fig. 2 – LED Sequencing using Array Data Structure – tinkercad.com

We use a protoboard to facilitate the connections, but you can also connect the wires directly to the Arduino.

The Code

The code can be implemented in the normal way in programming, as shown in the code below. But the code is quite large, we use 42 lines of code to create this kind of sequential LED circuit. To write less lines of code, an “optimizer” is required.

// Arduino: Lesson 9 - LED Sequencing using Array Data Structure
const int Led1 =  2;     // Select the output LED1 PIN
const int Led2 =  3;     // Select the output LED2 PIN
const int Led3 =  4;     // Select the output LED3 PIN
const int Led4 =  5;     // Select the output LED4 PIN
const int Led5 =  6;     // Select the output LED5 PIN
void setup() {            // This function is called once when the program starts
  pinMode(Led1, OUTPUT);  // Initialize digital pin LED1 as an output.
  pinMode(Led2, OUTPUT);  // Initialize digital pin LED2 as an output.
  pinMode(Led3, OUTPUT);  // Initialize digital pin LED3 as an output.
  pinMode(Led4, OUTPUT);  // Initialize digital pin LED4 as an output.
  pinMode(Led5, OUTPUT);  // Initialize digital pin LED5 as an output.
}
void loop() {                           // The loop function runs over and over again as long as the Arduino has power.
  // Turn ON each LED sequence in order
  digitalWrite(Led1, HIGH);
  delay(150);               // Wait for 150 millisecond(s)
  digitalWrite(Led2, HIGH);
  delay(150);               // Wait for 150 millisecond(s)
  digitalWrite(Led3, HIGH);
  delay(150);               // Wait for 150 millisecond(s)
  digitalWrite(Led4, HIGH);
  delay(150);               // Wait for 150 millisecond(s)
  digitalWrite(Led5, HIGH);
  delay(150);               // Wait for 150 millisecond(s)
  // Turn OFF each LED sequence in order
  digitalWrite(Led1, LOW);
  delay(150);               // Wait for 150 millisecond(s)
  digitalWrite(Led2, LOW);
  delay(150);               // Wait for 150 millisecond(s)
  digitalWrite(Led3, LOW);
  delay(150);               // Wait for 150 millisecond(s)
  digitalWrite(Led4, LOW);
  delay(150);               // Wait for 150 millisecond(s)
  digitalWrite(Led5, LOW);
  delay(150);               // Wait for 150 millisecond(s)
}
//------------------------------------- www.elcircuits.com --------------------------------------------

This is where the Array data structure comes into play, we can use it to drastically reduce the number of lines of code, as shown in the code example below.

// Arduino: Lesson 9 - LED Sequencing using Array Data Structure
const int Leds = 5;                          //Number of LEDs in the circuit
const int PinLeds[Leds] = {2, 3, 4, 5, 6};   //LEDs connected to pins 2 to 6
void setup() {            // This function is called once when the program starts
  for (int i = 0; i < Leds; i++) {    // Go through each of the elements in our array
    pinMode(PinLeds[i], OUTPUT);  // And set them as OUTPUT
  }
}
void loop() {                                        // The loop function runs over and over again as long as the Arduino has power.
  for(int i = 0; i < Leds; i++) {    // Go through each of the Leds elements in our array
    digitalWrite(PinLeds[i], HIGH);   // And set each of the PinLeds in HIGH level
    delay(150);   // Wait 150 millis seconds, and back to structure For
  }
  for(int i = 0; i < Leds; i++) {    // Go through each of the Leds elements in our array
    digitalWrite(PinLeds[i], LOW);   // And set each of the PinLeds in LOW level
    delay(150);   // Wait 150 millis seconds, and back to structure For
  }
}
//------------------------------------- www.elcircuits.com --------------------------------------------

Using the Array Data Structure technique, we could practically save half a line of the previous code, that's really cool, right?

After building the circuit, connect your Arduino board to your computer, run the Arduino software (IDE), copy the code below and paste it into your Arduino IDE. But first let us understand the code line by line.

In Line 3, we declared the number of LEDs in the circuit.
In Line 4, We are using an Array to index each pin of the LEDs in the corresponding Arduino Ports.
In Line 6, we enter the void setup() function. This function is read only once when the Arduino is started.
In Line 7, we enter in the FOR structure control, to access each Leds element.
in Line 8, we set each PinLeds as OUTPUT, through each elements in ou array.
In Line 11, we enter in the loop() function does precisely what its name suggests, and loops consecutively.
In Line 12, we enter in the For structure control, to go through each of the Leds elements in our array.
In Line 13, we continue in the For structure control, and set each of the PinLeds in HIGH level, turn on Led by Led.
In Line 14, we enter in the delay function, to wait 150 millis seconds, and back to structure For while it is true.
In Line 16, we enter in the For structure control, to go through each of the Leds elements in our array.
In Line 17, we continue in the For structure control, and set each of the PinLeds in LOW level, turn off Led by Led.
In Line 18, we enter in the delay function, to wait 150 millis seconds, and back to structure For while it is true.

All ready! After you have assembled the entire circuit, and uploaded this code, what you should see is the sequence of LEDs turning on and off, giving the impression that the LEDs are moving forward.

Next Lesson

Arduino: Lesson 10 - How to Read Temperature and Humidity with Arduino, Using the DHT11 Sensor

Previous Lesson

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projects! Thank you for dedicating your time to this content.

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Arduino Lesson 8 – Using LDR Sensor and Serial Monitor Readings

Electronic Circuits — Sun, 17 Oct 2021 14:37:00 +0000

Using LDR Sensor and reading values on Serial Monitor

Welcome to Lesson 8 – Basic Arduino Course

In today’s lesson, we will learn how to use an LDR sensor and read values on a Serial Monitor with Arduino.

To measure light intensity, we will use the famous and widely used low-cost LDR (Light Dependent Resistor) sensor, to detect the intensity of light or darkness easily and cheaply.

LDR (Light Dependent Resistor) Sensor

LDR is a special type of resistor that passes higher voltage (low resistance) when light intensity is high and low voltage (high resistance) when darkness is low.

With this method, we can use it for example in projects such as:

Lack of Light Alarm – Triggers an alarm when power is cut.
Brightness Control – Used to control the brightness of a recording or filming environment for example.
Contrast Control Screen – Often used on mobile phones to automatically lower or increase the brightness of the Display.
Emergency Light – Automatically turns on when Light is cut.
Ticket Counter – Also used to count people at the entrance of an establishment.
Invasion Alarm – Used to trigger an alarm when there is an invasion of a monitored establishment.

In today’s example, we will use this sensor to measure numerical resistance and read these values from the serial monitor.

To do this, we will use Arduino analog port A0. We can use any analog port, in the case of Arduino Uno there are 6 ports; A0 to A5.

Hardware Required

Arduino Board
LDR – Sensor Dependent Light
100K ohms resistor – (Brown, black, yellow, gold)
Jumper Wires
Protoboard (optional)

The Circuit Connections

The circuit is very simple, we connect one leg of the LDR to positive 5V, and another leg to a 100K resistor in series with negative GND, and the same leg that takes the resistor and LDR, we connect to port A0, as shown in Figure 2 below.

Fig. 2 – Using LDR Sensor and reading values on Serial Monitor – tinkercad.com

We use a protoboard to facilitate the connections, but you can also connect the wires directly to the Arduino.

The Code

The analogRead() function reads the value from the specified analog pin. Arduino boards contain a multichannel, 10-bit analog to digital converter. This means that it will map input voltages between 0 and the operating voltage (5V or 3.3V) into integer values between 0 and 1023.

On an Arduino UNO, for example, this yields a resolution between readings of: 5 volts / 1024 units or, 0.0049 volts (4.9 mV) per unit.

After building the circuit, connect your Arduino board to your computer, launch Arduino Software (IDE), copy the code below and paste it into your Arduino IDE. But first let us understand the code line by line.

In Line 3, we declared sensorPin to select the analog input Pin A0 to connect the LDR.
In Line 4, we declared sensorValue as a variable to store the value coming from the LDR sensor.
In Line 6, we enter the void setup() function. This function is read only once when the Arduino is started.
In Line 7, we set the serial port for communication, we will read the numeric value from the LDR sensor.

// Arduino Lesson 8 - Using LDR Sensor and reading values on Serial Monitor with Arduino

int sensorPin = A0;      // Select the Analog input pin for LDR
int sensorValue = 0;       // Variable to store the value coming from the sensor

void setup() {            // This function is called once when the program starts
  Serial.begin(9600);   // Sets Serial Port for communication with bounce rate in 9600
}

void loop() {                                           // The loop function runs over and over again as long as the Arduino has power.
  sensorValue = analogRead(sensorPin);   // Read the value from the sensor
  Serial.println(sensorValue);             // Prints the values coming from the sensor on the Serial Monitor
}
//------------------------------------- www.elcircuits.com --------------------------------------------

In Line 10, we enter in the loop() function does precisely what its name suggests, and loops consecutively.
In Line 11, the sensorValue variable receives the value read from the sensorPin, which is the analog input Pin, and stores the read values.
In Line 12, the Serial.println() function prints the values from the variable sensorValue on the serial monitor screen.

Below you can see the full code, which we can be copying and pasting into your Arduino IDE, and uploading to the Arduino.

// Arduino Lesson 8 - Using LDR Sensor and reading values on Serial Monitor with Arduino

int sensorPin = A0;      // Select the Analog input pin for LDR
int sensorValue = 0;       // Variable to store the value coming from the sensor

void setup() {            // This function is called once when the program starts
  Serial.begin(9600);   // Sets Serial Port for communication with bounce rate in 9600
}

void loop() {                                           // The loop function runs over and over again as long as the Arduino has power.
  sensorValue = analogRead(sensorPin);   // Read the value from the sensor
  Serial.println(sensorValue);             // Prints the values coming from the sensor on the Serial Monitor
}
//------------------------------------- www.elcircuits.com --------------------------------------------

All ready! After you have assembled the entire circuit, and uploaded this code, open the Serial Monitor and what you will see is the numerical value of the LDR.

When you approach your hands to the LDR, inhibiting the light, the number will drop to the minimum possible, it will depend on the LDR, and when you shine a light on the sensor, the number will go to the maximum of the sensor.

With that, the possibilities are immense to work with this sensor.

Next Lesson

Arduino: Lesson 9 – LED Sequencing using Array Data Structure

Previous Lesson

✨ Our Gratitude and Next Steps

We sincerely hope this guide has been useful and enriching for your projects! Thank you for dedicating your time to this content.

Your Feedback is Invaluable:

Have any questions, suggestions, or corrections? Feel free to share them in the comments below! Your contribution helps us refine this content for the entire ElCircuits community.

If you found this guide helpful, spread the knowledge!

🔗 Share This Guide

Best regards,
The ElCircuits Team ⚡

O post Arduino Lesson 8 – Using LDR Sensor and Serial Monitor Readings apareceu primeiro em Electronic Circuits.

Arduino Lesson 7 – Controlling LED via Serial Monitor

Electronic Circuits — Sun, 10 Oct 2021 23:39:00 +0000

Arduino: Lesson 7 – Controlling LED Through Serial Monitor with Arduino

Welcome to Lesson 7 – Basic Arduino Course

In today’s lesson, we will learn how to control the state of a LED via the Serial Monitor using the Arduino IDE.

We will use the Serial.readString() function which will cause the Arduino to interpret the sentence you have entered into the serial monitor, e.g. “Turn on the led“. If you press ENTER Key in your computer, the LED will be turned on, if you want to turn off the LED just write the message “Turn off the LED“.

With this method we can use it in different projects such as:

Load activation – Turns one or more loads on or off using commands.
Motor Speed Control – Use Serial Monitor to send the speed at which a PWM motor should run.
Calibrate a sensor’s constant – We can create software to change a sensor’s constant to a specified value if needed.

In our example today, we are using the serial monitor to trigger a LED, but you can also use a relay module to drive a motor, for example.

To do this, we will use the D9 digital port on Arduino. We can use any digital port we want. Just change the port you want to use in the declaration or the one that is available on your Arduino.

Required hardware

Arduino board
LED – Light Emitter Diode 220 Ohm Resistor – (red, red, brown, gold)
Jumper wires
Protoboard (optional)

The circuit

The circuit is quite simple. We connect a LED in series with a 220 ohm resistor to limit the current in the LED as we learned in previous lessons, and we connect the 9-pin of the Arduino UNO as shown in Figure 2 below.

Fig. 2 – Controlling LED Through Serial Monitor with Arduino – tinkercad.com

We use a protoboard to facilitate the connections, but you can also connect the wires directly to the Arduino.

The code

The Serial.readString() function reads characters from the serial buffer and moves them to a given string.

In our example, we want to do something very simple, which is to turn on and off a LED using the command from Serial Monitor.

After building the circuit, connect your Arduino board to your computer, run the Arduino software (IDE), copy the code below and paste it into your Arduino IDE. But first let us understand the code line by line.

// Arduino: Lesson 7 - Controlling LED Through Serial Monitor with Arduino

int ledPin = 9;      // LED connected to digital pin 9
String DataIn;       // String that will receive the Serial Monitor commands

void setup() {            // This function is read only once when the Arduino is started
  Serial.begin(115200);   // Begin Serial Monitor with bounce rate in 115200
  pinMode(ledPin, OUTPUT);  // Set the digital pin as output:
}

void loop() {                                           // The loop function runs over and over again as long as the Arduino has power.
  if (Serial.available()) {  // Check if there is any data on the serial monitor
    DataIn = Serial.readString();  // String DataIn receives the data typed in the Serial Monitor
  }
  if (DataIn == "turn led on") {  // Check if the received String is equal to "turn led on"
    digitalWrite(ledPin, HIGH);  // If yes, the function digitalWrite turns Led ON
  }
  if (DataIn == "turn led off") {  // Check if the received String is equal to "turn led off"
    digitalWrite(ledPin, LOW);   // If yes, the function digitalWrite turns Led OFF
  }
}
//------------------------------------- www.elcircuits.com --------------------------------------------

In Line 11, we enter in the void loop() function does precisely what its name suggests, and loops consecutively.
In Line 12, we enter in a if conditional, for to check if the Serial Monitor is available, if yes we call the next function.
In Line 13, we call the Serial.readString() function to read the characters from the Serial Monitor and send them to the String DataIn.
In Line 15, we enter in a if conditional, in this case to compare if the characters are the same as written in the Serial Monitor, in our example “turn led on“, if yes…
In Line 16, we enter the digitalWrite function, command activates ledPin to HIGH level, it means that it goes from 0V to 5V, which turn the LED On.
In Line 17, we enter in a if conditional, that compare if the characters are the same as written in the Serial Monitor, in our example “turn led off“, if yes…
In Line 18, we enter the digitalWrite function, command disables ledPin to LOW level, it means that it goes from 5V to 0V, which turn the LED Off.

// Arduino: Lesson 7 - Controlling LED Through Serial Monitor with Arduino

int ledPin = 9;      // LED connected to digital pin 9
String DataIn;       // String that will receive the Serial Monitor commands

void setup() {            // This function is read only once when the Arduino is started
  Serial.begin(115200);   // Begin Serial Monitor with bounce rate in 115200
  pinMode(ledPin, OUTPUT);  // Set the digital pin as output:
}

void loop() {                                           // The loop function runs over and over again as long as the Arduino has power.
  if (Serial.available()) {  // Check if there is any data on the serial monitor
    DataIn = Serial.readString();  // String DataIn receives the data typed in the Serial Monitor
  }
  if (DataIn == "turn led on") {  // Check if the received String is equal to "turn led on"
    digitalWrite(ledPin, HIGH);  // If yes, the function digitalWrite turns Led ON
  }
  if (DataIn == "turn led off") {  // Check if the received String is equal to "turn led off"
    digitalWrite(ledPin, LOW);   // If yes, the function digitalWrite turns Led OFF
  }
}
//------------------------------------- www.elcircuits.com --------------------------------------------

Below you can see the full code, which we can be copying and pasting into your Arduino IDE, and uploading to Arduino.

The complete code is showed in the sketch below!

// Arduino: Lesson 7 - Controlling LED Through Serial Monitor with Arduino

int ledPin = 9;      // LED connected to digital pin 9
String DataIn;       // String that will receive the Serial Monitor commands

void setup() {            // This function is read only once when the Arduino is started
  Serial.begin(115200);   // Begin Serial Monitor with bounce rate in 115200
  pinMode(ledPin, OUTPUT);  // Set the digital pin as output:
}

void loop() {                                           // The loop function runs over and over again as long as the Arduino has power.
  if (Serial.available()) {  // Check if there is any data on the serial monitor
    DataIn = Serial.readString();  // String DataIn receives the data typed in the Serial Monitor
  }
  if (DataIn == "turn led on") {  // Check if the received String is equal to "turn led on"
    digitalWrite(ledPin, HIGH);  // If yes, the function digitalWrite turns Led ON
  }
  if (DataIn == "turn led off") {  // Check if the received String is equal to "turn led off"
    digitalWrite(ledPin, LOW);   // If yes, the function digitalWrite turns Led OFF
  }
}
//------------------------------------- www.elcircuits.com --------------------------------------------

All ready! After you have assembled the entire circuit, and uploaded this code, open the Serial Monitor and what you will see is the numerical value of the LDR.

With that, the possibilities are immense to work with this sensor.

Next Lesson

Previous Lesson

✨ Our Gratitude and Next Steps

We sincerely hope this guide has been useful and enriching for your projects! Thank you for dedicating your time to this content.

Your Feedback is Invaluable:

Have any questions, suggestions, or corrections? Feel free to share them in the comments below! Your contribution helps us refine this content for the entire ElCircuits community.

If you found this guide helpful, spread the knowledge!

🔗 Share This Guide

Best regards,

The ElCircuits Team ⚡

O post Arduino Lesson 7 – Controlling LED via Serial Monitor apareceu primeiro em Electronic Circuits.

Understanding Electromagnetic Relays – Characteristics & Applications

Electronic Circuits — Sun, 03 Oct 2021 13:04:00 +0000

Electromagnetic Relays: Types, Operation, Characteristics and Applications!

Electromagnetic Relays: Understanding Operation and Practical Applications

🌐 You can read this article in: Português | Español

Hello Everyone!

Have you ever imagined how a simple component the size of a coin can control industrial motors or entire electrical systems? That’s exactly what electromagnetic relays do. They are the “bridge” between weak signals and high-power circuits, essential in home automation, industrial machines, and even household appliances..

In today’s post, we’ll explore in detail the operation, characteristics, and practical applications of electromagnetic relays.

🔍 Why are Relays so Important?

Electromagnetic relays are fundamental components in electronics and automation, functioning as electrically controlled switches. They allow a low-power circuit to control a high-power circuit safely and in isolation, being essential in numerous applications, from simple hobby projects to complex industrial systems.

🤔 What is an Electromagnetic Relay?

An electromagnetic relay is an electromechanical device that uses voltage, converts it into electromagnetic force, forming a magnetic field to control the switching of electrical contacts. It is composed of a small coil, a movable armature with spring, and switching contacts.

When a current flows through the coil, the electromagnet is activated, attracting the movable armature and switching the contacts. This allows a low-power signal to control a high-power circuit.

💡 Analogy for Better Understanding

Think of a relay as a light switch controlled by a magnet. When you turn on the switch (energize the coil), the magnet attracts a lever (armature) that closes or opens another electrical circuit. This allows you to control a high-power lamp using only a small low-power switch!

ℹ️ Main Types of Relays

There are several types of relays, each designed to meet specific needs. The main types include:

Relay Type	Characteristics	Typical Applications
Electromagnetic	Uses coil and contact system	Motor control, home automation
Solid State (SSR)	No moving parts, uses semiconductors	Temperature control, LED lighting
Thermal	Monitors temperature, uses bimetallic strip	Overload protection, climate control
Time	Controls operation time	Soft motor starting, irrigation

1. Electromagnetic Relay

Characteristics: The most common, use a coil and a contact system to control current flow.
Operation: Uses a coil to generate magnetic field and move contacts.
Applications:

Switching in electronic circuits, power supplies, switches.
Control of electric motors
Home automation systems (e.g., smart lighting)
Industrial safety circuits

Fig. 2 – Example of Industrial Electromagnetic Relay

2. Solid State Relay (SSR)

Characteristics: No moving parts, use semiconductor components to control current flow.
Advantages: No moving parts, longer lifespan and silent operation.
Applications:

Load driving circuits
Temperature control in industrial furnaces
High-frequency LED lighting

Fig. 3 – Example of Solid State Relay

🌟 Advantages of Solid State Relays

Silent operation (no mechanical clicks)
High switching speed
Less wear (no moving parts)
Galvanic isolation between input and output
Resistant to vibrations and mechanical shocks

3. Thermal Relay

Characteristics: Monitor temperature and disconnect the circuit when overheating occurs.
How it works: Uses a bimetallic strip that deforms with heat.
Applications:

Overload protection in electric motors
Climate control systems

Fig. 4 – Example of a Thermal Relay

4. Time Relay

Characteristics: Allow control of the operation time of electrical circuits.
Functionality: Adds programmable delays to switching.
Applications:

Soft motor starting
Automatic irrigation systems

Fig. 5 – Example of a Time Relay

⏱️ Types of Time Relays

Time relays can be classified as:

On energization: start counting when they receive power
On de-energization: start counting when power is cut off
Cyclic: automatically alternate between on/off states
Star-delta: specific for starting three-phase motors

👨‍🔧 Operation of the Electromagnetic Relay (Our Focus)

The operation of an electromagnetic relay can be understood by analyzing its internal structure, as illustrated in Figure 6 below. The electromagnetic coil is the heart of the relay, responsible for generating the magnetic field that switches the contacts.

Fig. 6 – Schematic diagram of an electromagnetic relay

1️⃣ Coil Energization: When a current flows through the coil, a magnetic field is generated.
2️⃣ Contact Switching: The magnetic field attracts the movable armature, switching the contacts from NC (Normally Closed) to NO (Normally Open).
3️⃣ De-energization: When the current in the coil ceases, the movable armature returns to its original position due to the spring force, switching the contacts back to NC.

Fig. 7 – Operation of the Electromagnetic Relay in Practice

🛠️ Characteristics and Architecture of an Electromagnetic Relay – Standard 5-Pin Model

In Figure 8 below, we present a 5-pin electromagnetic relay, which will serve as a reference to exemplify its internal architecture. This type of relay is widely used, being considered a standard model for its simplicity, availability in the market and ease of understanding.

Fig. 8 – Characteristics and Architecture of an Electromagnetic Relay – Standard 5-Pin Relay

In general, most electromagnetic relays available today are composed of five fundamental elements, which work in conjunction to perform electrical switching. They are:

1. Electromagnetic Coil

Responsible for generating the magnetic field when energized.

2. Movable Armature

Moving part that switches the contacts when attracted by the magnetic field.

3. Switching Contacts

NC (Normally Closed), NO (Normally Open) and COM (Common).

4. Magnetic Core

Improves the efficiency of the magnetic field.

5. Return Mechanism

Usually a spring that returns the armature to the original position.

These components form the functional core of the relay, enabling the actuation of electrical circuits safely and in isolation, as illustrated in Figure 9 below.

Fig. 9 – Internal architecture of an Electromagnetic Relay – Standard 5-Pin Relay

🧲 Configuration of the Electromagnetic Relay

Electromagnetic relays can have different configurations, and named with designations such as:

➡️ SPST (Single Pole Single Throw)

The SPST relay has a total of four terminals. Of these two terminals can be connected or disconnected. The other two terminals are necessary for the coil to be connected.

➡️ SPDT (Single Pole Double Throw)

The SPDT relay has a total of five terminals. Of these two are the coil terminals. A common terminal is also included, which connects to any of the other two.

➡️ DPST (Double Pole Single Throw)

The DPST relay has a total of six terminals. These terminals are divided into two pairs. Thus, they can act as two SPST, actuated by a single coil. Of the six terminals, two of them are coil terminals.

➡️ DPDT (Double Pole Double Throw)

The DPDT relay is the largest of all. It mainly has eight relay terminals. Of these two rows are designed to be switched by terminals. They are designed to act as two SPDT relays that are actuated by a single coil.

Each configuration offers different switching possibilities.

Configuration	Number of Terminals	Controlled Circuits	Typical Application
SPST	4	1 simple circuit	Simple on/off switching
SPDT	5	1 circuit with 2 options	Selection between two sources
DPST	6	2 independent circuits	Simultaneous control of 2 circuits
DPDT	8	2 circuits with 2 options each	Polarity reversal, complex selection

🔗 Related Content

If you liked this project, you might also be interested in these other articles:

How to Read Ceramic and Polyester Capacitors Correctly

How ATX Power Supplies Work: The Definitive 10-Step Guide

🧱 Applications of Relays

Relays are widely used in various applications:

⚙️ Motor Control

To turn on and off electric motors in industrial and residential systems.

🛡️ Circuit Protection

Overload relays protect motors and circuits against overloads.

🏭 Industrial Automation

In industrial control systems for process automation.

🚨 Alarm and Security Systems

For control of alarms and residential and industrial security systems.

🔧 Practical Examples in Daily Life

Automotive: Relays control headlights, horns and fuel pumps
Residential: Thermostats and automated lighting systems
Appliances: Microwaves, washing machines and refrigerators
Telecommunications: Switching in telephone and network systems

💡 How to Choose the Ideal Relay: Essential Tips for Safe and Efficient Selection

The correct choice of a electrical relay is fundamental to ensure safety, durability and performance in your automation or control system. See the main factors to consider when selecting a relay:

1. Contact and Coil Protection

Contact protection

Minimizes wear caused by electrical arcs, especially in circuits with inductive loads.

Coil protection

Avoids voltage surges during switching, extending the life of the relay and protecting the circuit components.

2. Certifications and Technical Compliance

Opt for relays that have recognized regulatory approvals (such as UL, CE and IEC), ensuring compliance with electrical safety standards and reliability.

3. Switching Time

For applications that require speed, such as protection systems, choose high-speed relays, which offer optimized response times.

4. Electrical Ratings

Current

Relays range from low current models to industrial relays up to 3,000 A.

Voltage

Options range from 300 V AC to 600 V AC, and can reach 15,000 V in specific high-voltage models.

Application	Recommended Relay Type	Key Specifications
Home automation	Electromagnetic or SSR	5-10A, 12-24V DC or 110-220V AC
Industrial motor control	Industrial electromagnetic	20-100A, 24-380V AC
Thermal protection	Thermal relay	Adjustable for motor current
High-frequency circuits	Solid State (SSR)	Low noise, high speed

✅ Checklist for Selecting the Ideal Relay

Check the coil voltage
Confirm the current capacity of the contacts
Evaluate the load type (resistive/inductive)
Consider the operating environment

Check safety certifications
Evaluate mechanical and electrical life
Consider the necessary switching time
Check galvanic isolation

🧾 Conclusion

Electromagnetic relays are versatile and essential devices in many applications. Understanding their operation and characteristics is crucial to use them efficiently. If you are designing a circuit or automation system, relays offer a reliable and effective solution for controlling electrical circuits.

📝 Key Points to Remember

Electromagnetic relays function as switches controlled by magnetism
They allow low-power circuits to control high-power circuits
There are different types of relays for specific applications
Proper relay selection is fundamental for system safety and efficiency
Relays continue to be essential components even with the advancement of electronics

❓ Frequently Asked Questions

Find answers to common questions about this amplifier circuit below.

Can I use this amplifier with 4Ω speakers? 🔽

Arquivo de Learning - Electronic Circuits

Ohm’s Law: The Definitive Guide | Theory, Formulas (V=I.R), and 5 Real-World Applications

📜 The History Behind the Law: Who was Georg Ohm?

🧐 What is Ohm's First Law? The Simplified Concept

🔑 The Best Analogy: Understanding Ohm's Law with Water

🧪 The Three Essential Formulas of Ohm's Law

1️⃣ To calculate Voltage (V)

2️⃣ To calculate Current (I)

3️⃣ To calculate Resistance (R)

🪛 Practical Examples: Applications of Ohm's Law in Circuits

🤔 Frequently Asked Questions (FAQ)

Varistor Explained: How It Works and Where to Use It

🧐 How Varistors Work: The Protection Mechanism

🔧 Types of Varistors: Know the Variations

1️⃣ Zinc Oxide Varistor (MOV)

2️⃣ Zinc Oxide Varistor with Bismuth

🔽 The main advantages of the zinc oxide varistor with bismuth addition include:

3️⃣ Metal Oxide Varistor (MO)

4️⃣ Silicon Carbide Varistor (SiC)

💡How Voltage Change Affects the Varistor's Resistance?

🔌 Varistor Symbol

👉 How Does a Varistor Help Suppress Voltage Transients?

📊 Voltage-Current (V-I) Characteristics

🛡️ Practical Applications of Varistors

⚠️ How to Select the Appropriate Varistor

🔗 Related Content

🧾Conclusion: The Invisible Guardian of Electronic Circuits

🤔 Frequently Asked Questions (FAQ)

Arduino Lesson 9 – LED Sequencing with Arrays (Practical Guide)

Welcome to Lesson 9 – Basic Arduino Course

What is Array?

Hardware Required

The Circuit Connections

The Code

Next Lesson

Previous Lesson

Arduino Lesson 8 – Using LDR Sensor and Serial Monitor Readings

Welcome to Lesson 8 – Basic Arduino Course

LDR (Light Dependent Resistor) Sensor

Hardware Required

The Circuit Connections

The Code

Next Lesson

Previous Lesson

Arduino Lesson 7 – Controlling LED via Serial Monitor

Welcome to Lesson 7 – Basic Arduino Course

With this method we can use it in different projects such as:

Required hardware

The circuit

The code

The complete code is showed in the sketch below!

Next Lesson

Previous Lesson

Understanding Electromagnetic Relays – Characteristics & Applications

Electromagnetic Relays: Understanding Operation and Practical Applications

🔍 Why are Relays so Important?

🤔 What is an Electromagnetic Relay?

💡 Analogy for Better Understanding

ℹ️ Main Types of Relays

1. Electromagnetic Relay

2. Solid State Relay (SSR)

🌟 Advantages of Solid State Relays

3. Thermal Relay

4. Time Relay

⏱️ Types of Time Relays

👨‍🔧 Operation of the Electromagnetic Relay (Our Focus)

🛠️ Characteristics and Architecture of an Electromagnetic Relay – Standard 5-Pin Model

1. Electromagnetic Coil

2. Movable Armature

3. Switching Contacts

4. Magnetic Core

5. Return Mechanism

🧲 Configuration of the Electromagnetic Relay

➡️ SPST (Single Pole Single Throw)

➡️ SPDT (Single Pole Double Throw)

➡️ DPST (Double Pole Single Throw)

➡️ DPDT (Double Pole Double Throw)

🔗 Related Content

If you liked this project, you might also be interested in these other articles: How to Read Ceramic and Polyester Capacitors Correctly How ATX Power Supplies Work: The Definitive 10-Step Guide

🧱 Applications of Relays

If you liked this project, you might also be interested in these other articles:

How to Read Ceramic and Polyester Capacitors Correctly

How ATX Power Supplies Work: The Definitive 10-Step Guide