Friday, April 1, 2022

140W Class AB Amplifier using MJL4281A and MJL4302A transistors with PCB

Fig. 1 - 140W Class AB Amplifier using MJL4281A and MJL4302A transistors with PCB

This is a simple 140W Class AB amplifier using MJL4281A and MJL4302A transistors, which stands out for its simplicity, quality, and is a moderate amplifier to build.

You can be making two of these boards, to be able to work with two outputs, in stereo, and make an amplifier with total power of 280W RMS.

This amplifier works with a simple power supply, that is, a unipolar, non-symmetric power supply.
 
This amplifier circuit can be used in almost any type of application that requires a simple amplifier, with great performance, low noise and low distortion, and good sound quality.

It uses 2 output power transistors, NPN transistor MJL4281, and PNP transistor MJL4302, forming a pair of complementary transistors.

You might also be interested in:

The Power Transistors

The MJL4281A and MJL4302A transistors are power transistors designed for high power audio, they have a collector-emitter sustaining voltage of 350 V.

It's high gain – 80 to 240, with the hFE = 50 (min) 8A collector current, and a low harmonic distortion, which makes a transistor excellent for high power operation and audio quality.

The Circuit

This circuit has a moderate complexity, it is not recommended for those who have no experience in electronics and in the assembly of amplifier circuits.

You should have minimum knowledge in an intermediate to advanced level to assemble this type of power amplifier.

The schematic diagram of the complete circuit, shown in Figure 2 below, is a very robust amplifier, with great sound quality and very stable, responding very well at all audible frequencies, with little attenuation in the 20Hz to 20Khz hearing frequency range.

Fig. 2 - Schematic Diagram 140W Class AB Amplifier using MJL4281A and MJL4302A transistors

Power supply

The power supply is symmetrical, with a voltage of +45V | 0V | -45V, and direct current, with at least 6 Amps of current. For continuous use, we recommend 4A, especially if used in a subwoofer.

In Figure 3 below, we have a suggestion for a power supply that we use in our projects. In this article, besides having the schematic diagram with the Printed Circuit Board, you will understand how to easily calculate your own Power Supply, with the desired voltage.

You can in the link below:

Fig. 3 - Symmetrical Power Supply for Power Amplifiers

Components List

  • Semiconductor
    • Q1, Q2, Q3 .... 2N5551 NPN Transistor
    • Q4, Q6 ........... BD139 NPN Transistor
    • Q5, Q7 ........... BD140 PNP Transistor
    • Q8 .................. MJL4302A NPN Transistor
    • Q9 .................. MJL4281A NPN Transistor
    • LED1 ............. Light Emitter Diode (general use

  • Resistor
    • R1, R3 ........... 2K2Ω resistor (red, red, red, gold
    • R2, R4, R8 ..... 22KΩ resistor (red, red, orange, gold)
    • R5, R6 ........... 560Ω resistor (green, blue, brown, gold)
    • R7 .................. 1K2Ω resistor (brown, red, red, gold)
    • R9 .................. 1KΩ resistor (brown, black, red, gold)
    • R10, R11 ....... 3K3Ω resistor (orange, orange, red, gold)
    • R12, R13 ....... 220Ω resistor (red, red, brown, gold)
    • R14, R15 ....... 0.22Ω / 5W resistor (red, red, silver, gold)
    • R16 ................ 10Ω / 1W resistor (brown, black, black, gold
    • RP1 ................ 2K Potentiometer
  • Capacitor
    • C1 .................. 2.2uF / 25V electrolytic capacitor 
    • C2 .................. 330pF ceramic, polyester capacitor
    • C3, C5 ........... 100uF / 65V electrolytic capacitor 
    • C4, C6, C7 .... 100nF ceramic, polyester capacitor

  • Miscellaneous 
    • P1, P2 ............ Screw Terminal Type 5mm 2-Pin Connector
    • P3 .................. Screw Terminal Type 5mm 3-Pin Connector
    • Others ............ PCB, tin, wires, heat sink, soldering Iron, etc.

Printed Circuit Board - Download

We are offering the PCB – Printed Circuit Board, in GERBER, PDF and PNG files, for you who want to do the most optimized assembly, either at home.

If you prefer in a company that develops the board, you can is downloading and make the files in the Download option below.

Fig. 3 - PCB - 140W Class AB Amplifier using MJL4281A and MJL4302A transistors

Files to Download, Direct Link:

Click on the link beside: GERBER, PDF and PNG files

If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.

Subscribe to our blog!!! Click Here - elcircuits.com!!!

My Best Regards!!!

Monday, March 28, 2022

110/220VAC 4 Step Control Touch Dimmer Switch Lamp Circuit with PCB

Fig. 1 110/220VAC 4 Step Control Touch Dimmer Switch Lamp Circuit with PCB

This type of circuit is widely used in lampshades that are sold in residential lighting stores, it activates an incandescent bulb through the touch on the device's casing.

It works as a dimmer with 4 pre-set levels, activated by touching a part of the sensor with your finger, which can be a metallic point, or a metallic housing, etc. The entire 4-level brightness control circuit is based on the LS7237 IC.

LS7237 IC Description

LS7237 is a 8-Pin monolithic, MOS integrated circuit designed to control the brightness of an incandescent lamp, as show in Figure 2 above. The output of the LS7237 triggers a Triac connected in series with a lamp. 
Fig. 2 - Pinout LS7237


The lamp brightness is determined by controlling the output conduction angle (Triac triggering angle) in relation to the AC line frequency.

CAUTION!!!

This circuit works directly connected to the 110/220V electrical network, and has a high power load, any carelessness, or wrong connections, error in the project, or any other occasion, can lead to irreversible damage. 

We are not responsible for any type of event. If you do not have enough experience to assemble this circuit, do not do it, and if you do, when testing, be sure to have the proper protections and be accompanied by someone else.

How the Circuit Work

The circuit works as follows: when a touch is made to the board, it causes the brightness of the lamp to change in specified steps as follows:
  • LEVEL - - - BRIGHTNESS(% Rated Wattage)
  • Off .................... 0
  • Night Light ....... 9
  • Mood Light ...... 29
  • Medium ............ 66
  • Maximum ......... 99

After AC power-up, the output comes up in the OFF state. Following that, every time the Touch Plate is touched, the output steps to the next level of brightness. The next step following the maximum brightness is the OFF state, initiating a new sequence.

Features

  • PLL synchronization allows use as a Wall Switch
  • Provides brightness control of an incandescent lamp with a touch plate or mechanical switch
  • Can control speed of shaded pole and universal AC motors
  • Controls the "duty cycle" from 23% to 88% (conduction angles for AC half-cycles between 45˚ and 158˚, respectively)
  • Operates at 50Hz/60Hz line frequency
  • Extension input for remote activation
  • +12V to +18V DC Power Supply (VSS - VDD)
  • 8-Pin Plastic DIP , 8-Pin SOIC

The Schematic Circuit

The 110/220VAC 4 Step Control Touch Dimmer Switch Lamp Circuit diagram is shown in Figure 3 below.  

Is a moderately simple circuit to assemble, with few external components, however one must have at least basic to advanced experience to assemble this circuit, if you are not experienced enough, ask someone more experienced to help you.

Fig. 3 - 110/220VAC 4 Step Control Touch Dimmer Switch Lamp Circuit

110Vac or 220Vac

This circuit was designed to work with 220Vac voltage, for use in 110Vac power network, the following components must be replaced in the component list.

  • R1, R2 .... 2.7MΩ 1/4W (red, violet, red, gold) 
  • R6 ........... 270Ω 1W (red, violet, brown, gold)
  • C5 ........... 330nF / 400V polyester Capacitor 
  • L1 .......... 60µH (RFI Filter)

Components List

  • Semiconductors
    • U1 ............ LS7237 Integrated Circuit
    • Q1 ............ BT136 Triac Transistor
    • D1 ............ 1N4007 Diode
    • DZ1 ......... 1N4744 15V/1W Zenner Diode 

  • Resistor
    • R1, R2 .... 4.7MΩ 1/4W (yellow, violet, green, gold) 
    • R3 ........... 1.8MΩ 1/4W (brown, gray, green, gold)
    • R4 ........... 1.5MΩ 1/4W (brown, yellow, green, gold)
    • R5 ........... 100Ω 1/4W (brown, black, brown, gold)
    • R6 ........... 1KΩ 2W (brown, black, red, gold)
  • Capacitor
    • C1 ........... 680pF / 400V Polyester Capacitor
    • C2 ............47nF / 400V Polyester Capacitor
    • C3 ........... 470pF/ 400V Ceramic Capacitor
    • C4 ........... 47µF / 25V Electrolytic Capacitor 
    • C5 ........... 220nF / 400V Polyester Capacitor
    • C6 ........... 150nF /400V polyester Capacitor

  • Miscellaneous 
    • L1 .......... 120µH (RFI Filter)
    • P1, P2 .... 2-pin PCB soldering terminal blocks
    • F1 .......... 3A/250V Soldering fuse
    • Others .... PCB, heat sink, power supply, wires, etc.

Printed Circuit Board - Download

We are offering the PCB - Printed Circuit Board, in GERBER, PDF and PNG files, for you who want to do the most optimized assembly, either at home.

If you prefer in a company that develops the board, you can is downloading and make the files in the Download option below.
Fig. 4 - PCB 110/220VAC 4 Step Control Touch Dimmer Switch Lamp Circuit

Files to download, Direct Link:


If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.

Subscribe to our blog!!! Click Here - elcircuits.com!!!

My Best Regards!!!

Saturday, March 26, 2022

How to Wire LEDs in 110V or 220 Volts - 6 Different Circuits! Formulas & Calculations!

Fig. 1 - How to Wire LEDs in 110V or 220 Volts - 6 Different Circuits! Formulas & Calculations!

Today we will show you 6 different ways to wire 3mm or 5mm LEDs, which are low voltage DC components, into a 110V or 220V AC voltage grid!

We can use LEDs in several ways connected to 110V or 220V power grid, knowing that some types of connections bring advantages over others, and that each type has its characteristics that best fit each specification. 

We will use some basic formulas to calculate the components in our circuit, for this we will use the capacitive reactance formula, and the Ohms Law formula.

So let's start by showing the basic formulas that we will use with the models we made in this post. 

We'll apply the basic formulas as needed, so we'll start first by determining the supply voltage. 

CAUTION! 

As simple as the circuits presented are, it is important to know that the circuit is connected to direct mains voltage, this is extremely dangerous, an oversight or design error, can cause irreversible damage.
Be cautious when handling electrical voltage, if you have no electronics/electrical experience, do not do this circuit.
If you are experienced, do it with caution, and always have someone nearby, do not handle mains-connected equipment when you are alone.
We are not responsible for any damage that happens to you or others.

The working voltage

In our country the working voltage is 110VAC, if your electrical network is 220VAC, just substitute the working voltage of your region in the formula.

It is necessary to know that our grid voltage has peak voltages, as showing in Figure 2 below, and for our safety we will use the peak to peak voltage (VPP) in our calculations.
Fig. 2 - Peak to Peak 110Vac Calculation - VPP

The calculation is determined by the mathematical equation:

  • VP = VAC * (2)

As our power grid is 110VAC:

  • VP = 110 *1.414
  • VP = 155.54VAC

If you use the 220VAC power grid:

  • VP = 220V * 1.414
  • VP = 311,08VAC

The LED

  • We will use a white LED, which in its specifications is 3.2V for 20mA, or 0.02A.

Determine the resistor resistance:

To determine the resistor resistance for the circuit, using the Ohms Law formula:
  • V = R * I
V = Voltage
R = Resistance 
I = Current

Determine the Resistor's Power:

And to determine the resistor's power we will also use Ohms' Law:
  • P = R * I²
P = Resistor Power
R= Resistor Value 
I = Current passing through the resistor.

Determine Capacitive Reactance:

Capacitive reactance is the opposition that a capacitor presents to the flow of current in AC circuits.

Capacitive reactance is represented by the notation Xc, and is expressed in ohms. To determine the capacitive reactance Xc, we will use the equation:
  • XC = 1 / (2 π  * F * C)
XC = Capacitive Reactance in Ω
π = 3,14 - Constant
F = AC Frequency in Hz
C = Capacitance in F

Knowing all the formulas that we will use in our circuits, let's start with the simplest to the most complex.

1° Circuit:

This model is the simplest we have, and it is very often used in cheap electrical extensions of those Chinese products, and also as a Pilot lamp in equipment,... 

The circuit presented has only one resistor R1, which limits the current that passes through the LED, and is connected in series with the LED, as we can see in Figure 3 below.

Fig. 3 - Wire LED in 110v or 220V Circuit 1 - ELC

Designing the Circuit

We need to determine the resistance to be used, for this we will use the ohms law formula:

General Formula:

  • V = R * I

Applying the formula to our circuit:

  • R = (VS - VL) / I 
VS = Peak mains voltage, which is 155.54Vac
VL = Voltage of the LED, which is 3.2V
IL = The LED current, which is 0.02A

Then:

  • R = (155,54 - 3.2) / 0.02
  • R = 152,34 / 0.02
  • R = 7.617R
As we know, when it comes to electronic components, there is the tolerance of the components that make up the circuit, such as the tolerance; of the resistor, the LED, and the variations "tolerance" coming from the Power grid.
For this reason, we give a tolerance margin of more or less 40% more in the load resistor, that is:
  • 7.617Ω + 40% = 3.047Ω
  • 7.617Ω + 3.047Ω = 10.6638Ω or 10.66KΩ
  • That is, the value of the closest commercial resistor, knowing that we always take the closest one with the highest value is 12KΩ.

We now need to determine the power of the resistor, for this we will use the ohms law formula:

General Formula:

  • P = R * I²

Then:

  • P = 12.000 * 0.02²
  • P = 4.8W

Project Finished - Circuit 1

We finish here the development of our circuit 1, the calculated values we will have:
  • LED1 ....... 3.2V / 20mA Light Emitting Diode
  • R1 ............ 12K / 5W Resistor for 110V. (27K to 220V).

Advantages:

  • It is a Simple and easy circuit to assemble
  • Only 2 components

Disadvantages:

  • Voltage dissipation will be on the resistor (Joule effect)
  • Consumption higher than necessary
  • Circuit operating in half wave, LED half off 
  • Short LED lifetime, reverse voltage on LED
  • Low Efficiency

2° Circuit:

This model is still quite simple, it is a circuit widely used also in cheaper electrical extensions of those Chinese products... 

The circuit presented has a resistor R1, which limits the current that passes through the LED, and a Diode, which polarizes the AC voltage coming from the power grid, which is connected in series with the LED, as we can see in Circuit 2.1 in Figure 4 below. .

We also have Circuit 2.2, which is the same circuit, but we have added a 2.2uF capacitor that serves to minimize the ripple voltage in the circuit. 

Fig. 4 - Wire LED in 110v or 220V Circuit 2 - ELC

Designing the Circuit

Just like the previous circuit, the calculations are the same, we already calculated the resistance, after all the process, it was 12K with 5W of power.

Project Finished - Circuit 2

Here we finish the development of our circuit 2, the calculated values are

  • LED1 ....... Light Emitting Diode 3.2V / 20mA
  • D1 ............ 1N4007 Diode
  • C1 ............ 2.2uF / 25V Electrolytic Capacitor (Optional)
  • R1 ............ 12K / 5W resistor for 110V. (27K at 220V).

Advantages:

  • It is a simple and easy circuit to assemble
  • Only 3 or 4 components
  • Safer circuit for LED lifetime

Disadvantages:

  • Voltage dissipation will be on the resistor (Joule effect)
  • Consumption higher than necessary
  • Circuit operating in half wave, LED half off
  • Low Efficiency

3° Circuit

This model, different from the previous one, adopts a rectifier bridge, this implies that the energy that comes to the LED, is no longer a half wave, but a full wave, which gives more brightness to the LED.

The circuit presented has a resistor R1, current limiter, and a bridge of diodes, which polarize the AC voltage that comes from the grid, and feeds the LED, as we can see in Circuit 2.1 in Figure 5 below.

We also have Circuit 2.2, which is the same circuit, but we add a 2.2uF capacitor that serves to minimize the ripple voltage in the circuit. 

Fig. 5 - Wire LED in 110v or 220V Circuit 3 - ELC

Designing the Circuit

Just like the previous circuit, the calculations are the same, we already calculated the resistance, after all the process, it was 12K with 5W of power.

Project Finished - Circuit 3

Here we finish the development of our circuit 2, the calculated values are

  • LED1 ....... Light Emitting Diode 3.2V / 20mA
  • D1 ............ 4 x 1N4007 Diode, or a diode bridge any model
  • C1 ............ 2.2uF / 25V Electrolytic Capacitor (Optional)
  • R1 ............ 12K / 5W resistor for 110V. (27K at 220V).

Advantages:

  • It is a simple circuit to assemble
  • Only 3 or 4 components
  • Full wave, which gives more brightness to the LED.
  • Safer circuit for LED lifetime

Disadvantages:

  • Voltage dissipation will be on the resistor (Joule effect)
  • Consumption higher than necessary
  • Low Efficiency

4° Circuit:

This model is simple, but works in a more efficient way, since the heat dissipation is no longer tied to the Current Limiting Resistor, which dissipated all the voltage in the previous circuits.

This circuit is widely used in Mosquito Bats, rechargeable flashlights, i.e. cheaper Chinese products. 

In this circuit we replaced the current limiting resistor with a capacitor. When a capacitor is connected to an AC source, it allows current to flow in a circuit.

With the process of successive charge and discharge of a capacitor, it gives rise to a resistance, in the passage of current in the circuit, and this resistance is called capacitive reactance. With these properties, we can use the capacitor in our circuit as a resistor.

In the case of the capacitor, all of this energy is used, because the capacitor needs to charge and discharge, it "holds" the energy and therefore does not consume it, making the circuit much more efficient. 

We also have Circuit 4.2, which is the same circuit, but we have added a 2.2uF capacitor that serves to minimize the ripple voltage in the circuit. The complete circuits are in Figure 6 below.

Fig. 6 - Wire LED in 110v or 220V Circuit 4 - ELC

Designing the Circuit

We need to determine the capacitive reactance to be used, for this we will use the Ohms' Law formula, it is exactly the formula used to figure out the resistance of R1 in the previous circuits.

Remember: The and I values are effective, so we will use the RMS voltage, not the VPP voltage. 

General Formula:

  • XC = (VS - VL) / IL 

Applying the formula to our circuit:

  • XC = (VS - VL) / I 
  • VS = Mains voltage, which is 110Vac
  • VL = Voltage of the LED, which is 3.2V
  • IL = The LED current, which is 0.02A

Then:

  • XC = (110 - 3.2) / 0.02
  • XC = 106.8 / 0.02
  • XC = 5.340Ω or 5.3K

Since we have already found out the Xreactance which is 5.340Ω or 5.3KΩ, we can now calculate the current that this capacitor will supply to our circuit. We will use the same formula as in Ohms' Law

General Formula:

  • I = VS  / XC
  • VS = Main voltagem in RMS
  • XC = Capacitive Reactance in Ω

Applying the formula to our circuit:

  • I = (VS - VL) / XC
VS = Mains voltage RMS, which is 110Vac
VL = Voltage of the LED, which is 3.2V
XC = Capacitive Reactance, which is 5.340Ω

Then:
  • I = (110 - 3.2) / 5.340
  • I = (106.8) / 5.340
  • I = 0.02A
  • I = 20mA
Knowing the resistance XC and current values in the circuit, we need to determine the capacitance of the capacitor. We will do this as follows below:

General Formula:
  • C = 1 / (2 π  * FXC

Since capacitance is usually not expressed in Farad but in a submultiple, we will use the rewritten formula, so that we can use the capacitor value in µF and make our calculations easier.

Applying the formula to our circuit:

  • C = 106 / (2 π * F * XC) 
C = Capacitance that we need to know
π = Is a constant 3.14
XC = Capacitive Reactance, which is 5.340Ω
F = Main frequency, which is 60Hz


Then:
  • C 106 / (2 * 3.14 * 60 * 5.340) 
  • C = 106 / (6.28 * 60 * 5.340) 
  • C = 106 / (376.8* 5.340) 
  • C = 106 / (2,012.112) 
  • C = 0.4969uF or 497nF
That is, the value of the closest commercial capacitor, knowing that we always take the closest one with the highest value is 560nF.

Project Finished - Circuit 4

We finish here the development of our circuit 4, the calculated values we will have:
  • LED1 ....... Light Emitting Diode 3.2V / 20mA
  • D1 ........... 1N4007 Diode
  • C1 ............ 560nF / 250V Polyester Capacitor
  • C2 ............ 2.2uF / 25V Electrolytic Capacitor (Optional)

Advantages:

  • No consumption of excess heat energy (Joule effect)
  • It is simple circuit to assemble
  • Only 3 or 4 components
  • High Efficiency
  • Safer circuit for LED lifetime

Disadvantages:

  • Circuit operating in half wave, LED half off 
  • High current in the initial steady state of the capacitor, causing those "pops" and sparks in the socket.

5° Circuit:

This model is a more complete and improved circuit, because it brings with it a diode bridge, improving efficiency even more, since the LED will no longer work for half a wave period, but for a full wave period.

This circuit is widely used in small luminaires, even in LED lamps, rechargeable flashlights, or in commercial products. 

This circuit is the junction of circuits 3 and 4, thus forming an efficient circuit, with good LED brightness, with full wave, it is almost the perfect circuit. 

The circuit presented has a diode bridge, which polarizes the AC voltage coming from the mains, which is connected in series with the LED, as we can see in Circuit 5.1 in Figure 7 below.

We also have Circuit 5.2, which is the same circuit, but we add a 2.2uF capacitor that serves to minimize the ripple voltage in the circuit.

Fig. 7 - Wire LED in 110v or 220V Circuit 5 - ELC

Designing the Circuit

First you need to determine the capacitive reactance, which was already done in the previous circuit, the capacitance is 5.340Ω or 5.3K.

Project Finished - Circuit 5

We finish here the development of our circuit 5, the calculated values we will have:
  • LED1 ....... Light Emitting Diode 3.2V / 20mA
  • D1 ........... 4 x 1N4007 Diode, or a diode bridge, any model
  • C1 ........... 560nF / 250V Polyester Capacitor
  • C2 ........... 2.2uF / 25V Electrolytic Capacitor (Optional)

Advantages:

  • It is a simple circuit to assemble
  • Only 3 or 4 components
  • Safer circuit for LED lifetime
  • No consumption of excess heat energy (Joule effect)
  • High Efficiency
  • Circuit operating in full wave, LED always on

Disadvantages:

  • High current in the initial steady state of the capacitor, causing those "pops" and sparks in the socket.

6° Circuit:

This model is more complete and, like the previous circuit, is more efficient. This circuit is widely used in small light fixtures, some LED lamps, rechargeable flashlights, and in some commercial products. 

The circuit presented is identical to circuit 5, with the only difference that we put a resistor R1, that serve to limit the capacitor inrush current. A diode bridge, which polarizes the AC voltage coming from the mains, which is connected in series with the LED, as we can see in Circuit 6.1 in Figure 8 below.

We also have Circuit 6.2, which is the same circuit, but we have added a 2.2uF capacitor that serves to minimize the ripple voltage in the circuit.

Fig. 8 - Wire LED in 110v or 220V Circuit 6 - ELC

Designing the Circuit

First you need to determine the resistance R1, the resistor value was chosen to limit the worst case inrush current to about 100mA which for safety, will be 5 times the current draw of the circuit, which will drop to less than 20mA in a millisecond as the capacitor charges.

In this case, we use ohms' law to figure out what resistor we will use.

General Formula:

  • V = R * I

Applying the formula to our circuit:

  • R = (VS - VL) / I 
  • VS = Mains voltage, which is 110Vac
  • VL = Voltage of the LED, which is 3.2V
  • IL = Inrush current, which is 0.1A or 100mA

Then:

  • R = (110 - 3.2) / 0.100
  • R = 106 / 0.100
  • R = 1,068Ω or ~1KΩ

Now, we need to determine the power of the resistor, for this we will use the ohms law formula:

General Formula:

  • P = R * I²

Then:

  • P = 1,068 * 0.02²
  • P = 0.427W

That is, the value of the closest commercial power resistor, knowing that we always take the closest one with the highest value is 1/2W.

Project Finished - Circuit 6

We finish here the development of our circuit 5, the calculated values we will have:
  • LED1 ....... Light Emitting Diode 3.2V / 20mA
  • D1 ........... 4 x 1N4007 Diode, or a diode bridge, any model
  • R1 ........... 1KΩ / 1/2W Resistor
  • C1 ........... 560nF / 250V Polyester Capacitor
  • C2 ............ 2.2uF / 25V Electrolytic Capacitor (Optional)

Advantages:

  • It is a simple circuit to assemble
  • Only 3 or 4 components
  • Safer circuit for LED lifetime
  • No consumption of excess heat energy (Joule effect)
  • High Efficiency
  • Circuit operating in full wave, LED always on

Disadvantages:

  • Can be better, by putting a resistor in parallel as a capacitor, to discharge it...

If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.

Subscribe to our blog!!! Click here - elcircuits.com!!!

My Best Regards!!!


Wednesday, March 16, 2022

How To Make Rechargeable Emergency LED Light Using LM350 IC with PCB

Fig. 1 - How To Make Rechargeable Emergency LED Light Using LM350 IC with PCB

You know that night when the power grid collapses and the power goes out, so we need a light to illuminate the darkness.

That's when we realized that we would need some equipment that could light up that darkness...

In this article, we are going to assemble a Rechargeable Automatic Emergency LED Light circuit that when the power goes out, it activates the set of LED lamps automatically using a rechargeable 12V battery.

You may be interested in: 

How the Circuit works

The Automatic Illuminator circuit is divided into three distinct parts:

The first part:

It's pretty obvious, we have the 220Vac or 110Vac voltage coming from the mains, and we need to convert it to 12Vac. For this, we use a 220V/12Vac transformer. The output of the 12Vac transformer, it is connected to a diode bridge to rectify the AC voltage to DC, and the 2200uF capacitor to filter this voltage.

The second part:

It is a 12V battery charging stage, it works simply as a charger, it has a status LED that when charging it stays on, and when charged the LED goes off.

The circuit uses the LM350T voltage regulator. The output current of the LM350 is 3 amps, it is necessary to adjust the output voltage through the trimpot of 4.7K, this voltage must be adjusted according to the battery used.

In some batteries this voltage is 13.8V, in others it is 14.4V, this is always described together in the general battery information.

For those who follow us here on our site, you may have already noticed that the 12V battery charger circuit is very similar to an article that we have already done here on our site, you can check it out by clicking on this link.

The Third part:

It is a control circuit composed of a BD140 PNP transistor, which works as a drive circuit, when there is power on the grid.

The voltage from the source passes through the 1K base current limiting resistor, and causes the transistor to stay open, keeping the light off, as soon as the voltage is cut off. 

The transistor as a switch closes the circuit, slinging the battery to the set of 20 LEDs, turning the light on.


The Circuit Diagram

The complete schematic diagram of the power supply is shown below in Figure 2, it is a simple but complete adjustable symmetric power supply.

Fig. 2 - Schematic Diagram Rechargeable Emergency LED Light Using LM350 IC

The Power Transformer

The transformer should have as primary according to your local network, 110Vac or 220Vac. The secondary should be 12V, since when we pass through the rectification, this 12Vac voltage is transformed more or less into 16.9Vdc.

The transformer should have a current of 3 amps, in case you are going to use it with large batteries, such as 7A, 9A, etc… 

If you are going to work with smaller batteries, it is up to you to place a transformer proportional to the total power of the LEDs and the battery used. The transformer configuration diagram is shown in Figure 4 below.
Fig. 3 - Schematic Diagram Transformer 110/220Vac to 12Vac 3Amps

Component List

  • Semiconductors
    • U1 ........................ LM350 Voltage Regulator  
    • Q1 ........................ BC548 NPN Transistor
    • Q2 ........................ BD140 PNP Transistor
    • D1 ........................ KBU4A - 4A Rectifier Bridge
    • D2 ........................ 1N5408 Diode Rectifier 
    • LED1 to LED20 ... Light Emitter Diode 5mm High Light
    • LED1 .................... Light Emitter Diode 3mm (general use)

  • Resistors
    • R1 ............... 100Ω 1/8w Resistor (brown, black, brown, gold
    • R2 ............... 0.5Ω 5W Resistor (green, black, silver, gold)
    • R3 ............... 470Ω 1/8w Resistor (yellow, violet, brown, gold
    • R4 ............... 120Ω 1/8w Resistor (brown, red, brown, gold
    • R5 ............... 1kΩ 1/8w Resistor (brown, black, red, gold
    • R6 to R10 ... 1Ω 3W Resistor (brown, black, black, gold)
    • RP1 ............. 4K7Ω Trimmer

  • Capacitors
    • C1 ...... 2.200uF - 25V Electrolytic capacitor 
    • C2 ...... 0.33uF - 25V Electrolytic capacitor 

  • Miscellanies
    • P1, P2 ....... Connector 2 screw terminal 5mm 2 Pins
    • T1 ............. Transformer Reduction 110/220ac to 12Vac (See Text)
    • Others ....... Wires, Solders, pcb, heat sink, etc.

PCB - Download

We provide the files with the PCB, the schematic, the PDF, GERBER and JPG, PNG and provide a direct link for free download and a direct link, "MEGA".

Fig. 4 - PCB - Rechargeable Emergency LED Light Using LM350 IC

Click on the direct link to download the files: Layout PCB, PDF, GERBER, JPG

If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.

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Sunday, March 6, 2022

1.5V to 28V, 7.5 Amps Adjustable Symmetric Power Supply using IC LT1083 with PCB

Fig.1 - 1.5V to 28V, 7.5 Amps Adjustable Symmetric Power Supply using IC LT1083 with PCB

This is a power supply designed to be used in a technical bench, based on the LT1083 integrated circuit, which is an adjustable 3-terminal positive voltage regulator

Which provides a current of 7.5A in a variable output voltage range of 1.5 to 28V, and even has short circuit and over temperature protection.
 
The Circuit provides a symmetrical output, which pleases all of us engineers, technicians and designers, this type of power supply, as it brings us great efficiency for application in technical benches, mainly for testing audio amplifiers.

LT1083 IC Description

The  LT1083  positive  adjustable  regulator  is designed to provide  7.5A with higher efficiency than currently  available  devices.  

In Figure 2 - You'll find the description of the input, output and ground pins. There are other types of encapsulation, as this TO - 3P is the most common.
Fig. 2 - Pinout LT1083

All  internal  circuitry  is designed to operate down to 1V input to output differential, and the dropout voltage is fully specified as a function of load current. 

Dropout is guaranteed at a maximum of 1.5V at  maximum  output  current,  decreasing  at  lower  load currents. 

On-chip trimming adjusts the output voltage to 1%. The current limit is also trimmed, minimizing the stress on both the regulator and power source circuitry under overload conditions.


The LT1083  series  devices  are  pin  compatible  with  older three terminal  regulators. A 10μF  output  capacitor  is required on these new devices; however, this is usually included in most regulator designs.

Unlike  PNP  regulators,  where  up  to  10%  of  the  output current is wasted as quiescent current, the LT1083 quiescent current flows into the load, increasing efficiency.

Features

  • Three-Terminal 3.3V, 3.6V, 5V, 12V or Adjustable
  • Output Current of 3A, 5A or 7.5A
  • Operates Down to 1V Dropout
  • Guaranteed Dropout Voltage at Multiple Current Levels
  • Line Regulation: 0.015%
  • Load Regulation: 0.1%
  • 100% Thermal Limit Functional Test
  • Adjustable Versions Available

How the Circuit Work

The circuit operation is quite simple, and its operation is applied with an artifice that we did to join two adjustable power sources into one.

Since we don't have "as far as I know", a regulator of the same negative line, like what happens with the regulators LM317, LM7812 and etc.

The bridges of diodes KBPC5010 D1 and D4, are responsible for rectifying the circuit, this diode bridge is able to support currents up to 50A

I know it's an exaggeration, but it was what I had here, you can be putting with lower current, as the KBPC1510, for 15A, or the KBPC1010 for 10A.

The capacitors C1 and C3, are electrolytic capacitors responsible for filtering the circuit, we use them of 10,000uF, but if you don't have one you can put one of 8,000uF. Remembering that they have to be able to avoid Ripple in the power supply.

The resistors R1 and R3 are the limiters for LED1 and LED2, which are used as voltage signaling for the two sources.

The voltage that comes already rectified and filtered enters the Positive Voltage Regulators, as we can see in the circuit, they are identical circuits, and through the double potentiometer the output voltage regulation is done, ranging from 1.5V to 28V.

The diodes D2, D3, D5, and D6, are for reverse voltage protection that can arise from the circuit and damage the Regulators, and the diodes protect these voltages in the regulators.

The resistors R2 and R4, are responsible for the Feedback voltage, or feedback, they keep the output voltage stable, they are resistors that if you have conditions, put the ones with low error percentage, such as precision resistors with 1%.

And finally, the capacitors C2 and C4, are for spurious filter, if you can afford it, it is preferable tantalum capacitors. 

The Circuit Diagram

The complete schematic diagram of the power supply is shown below in Figure 2, it is a simple but complete adjustable symmetric power supply.
Fig. 3 - Schematic Diagram 1.5V to 28V, 7.5 Amps Adjustable Symmetric Power Supply using IC LT1083 

The Power Transformer

The transformer must be symmetrical with center tape open, this means that it will to have two independent winding: "2 Wire + 2 Wire", as illustrated in Figure 4 below. 
Fig. 4 - Symmetrical Transformer with Independent secondary winding

The transformer must be able to supply 8A at the symmetrical output. The primary voltage, “input voltage”, must correspond to the voltage in your area; 110V or 220Vac

The secondary voltage, “output voltage”, should be 21Vac in each coil, because after rectification it will supply the circuit with 30Vdc.

Component List

  • Semiconductors
    • U1, U2 .................. LT1083 Voltage Regulator  
    • D1, D4 .................. KBPC5010 - 50A Rectifier Bridge *See Text
    • D2, D3, D5, D6 .... 1N4007 Diode Rectifier 
    • LED1, LED2 ........ Light Emitter Diode (General Use)

  • Resistors
    • R1, R3 ....... 2K7Ω 1/8w Resistor (red, violet, red, gold
    • R2, R4 ....... 120Ω 1/8w Resistor (brown, red, brown, gold
    • RP1 ........... 5KΩ Double Potentiometer 

  • Capacitors
    • C1, C3 ........ 10.000uF - 45V Electrolytic capacitor 
    • C2, C4 ........ 10uF - 45V Electrolytic capacitor 

  • Miscellanies
    • P1, P2 ........ Connector 2 screw terminal 5mm 2 Pins
    • P3 .............. Connector 3 screw terminal 5mm 3 Pins
    • Others ....... Wires, Power Transformer, Solders, pcb, heat sink, etc.

Download

We provide the files with the PCB, the schematic, the PDF, GERBER and JPG, PNG and provide a direct link for free download and a direct link, "MEGA".

Fig. 5 - PCB - 1.5V to 28V, 7.5 Amps Adjustable Symmetric Power Supply using IC LT1083

Click on the direct link to download the files: Layout PCB, PDF, GERBER, JPG

If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.

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My Best Regards!!!

Monday, February 28, 2022

25A - 110/220V Solid State Relay (SSR) Circuits using Triac BTA24-600 With PCB

Fig. 1 - 25A - 110/220V Solid State Relay (SSR) Circuits using Triac BTA24-600 With PCB

Solid State Relays (SSR) are nothing new, but making your own SSR is priceless! With it we can connect to digital control devices such as; Arduino, PIC, ESP, CLP, Raspberry, etc. 

Besides that, we can spend a fraction of the price of a commercial relay if we make our own SSR relay, and still have in our hands the control that if something goes wrong, we can repair it without too much trouble.

The Solid State Relay

Solid State Relay is similar to switching relays, they all function as a switch that is controlled by an input voltage or current, isolated from the output. 

The basic difference is that Solid State Relay, or (SSR), has no moving parts, but uses the electrical and optical properties of solid-state semiconductors.

Electromechanical Relays (EMR), on the other hand, use coils, magnetic fields, springs, and mechanical contacts to operate and switch through a supply voltage.

Our circuit uses few external components, and is easy to assemble, the components are easy to acquire in the market, and basically there are two:
  • The isolation circuit formed by the MOC3041optical isolator.
  • The power control formed by the BA24-600 TRIAC, they will be explained  just below.   

CAUTION!!!

This circuit works directly connected to the 110/220V electrical network, and has a high power load, any carelessness, or wrong connections, error in the project, or any other occasion, can lead to irreversible damage. 

We are not responsible for any type of event. If you do not have enough experience to assemble this circuit, do not do it, and if you do, when testing, be sure to have the proper protections and be accompanied by someone else.

BTA24 Description 

Available either in through-hole or surface-mount packages, the BTA24 TRIAC is suitable for general purpose AC switching. 

They can be used as an ON/OFF function in applications such as static relays, heating regulation, induction motor starting circuits... or for phase control operation in light dimmers, motor speed controllers.

The snubber-less versions (BTA/BTB...W and T25 series) are specially recommended for use on inductive loads, thanks to their high commutation performances. 

By using an internal ceramic pad, the BTA series provides voltage insulated tab (rated at 2500V RMS) complying with UL standards.

6-Pin  DIP  Zero-Cross Opto-isolators  Triac  Driver  Output

(400 Volts Peak)

The MOC3041, MOC3042 and MOC3043 devices consist of gallium arsenide infrared  emitting  diodes  optically  coupled  to  a  monolithic  silicon  detector performing the function of a Zero Voltage Crossing bilateral triac driver.

They  are  designed  for  use  with  a  triac  in  the  interface  of  logic  systems  to equipment powered from 115/220 Vac  lines,  such  as  solid–state  relays,  industrial controls, motors, solenoids and consumer appliances, etc.
  • Simplifies Logic Control of 115 Vac Power
  • Zero Voltage Crossing
  • dv/dt of 2000 V/μs Typical, 1000 V/μs Guaranteed

We are using the MOC3041 optical isolator, because of this model, having a zero-crossing SSR accepts triggering at any time, but delays the triggering of the AC load until the next time the AC voltage passes zero volts. 

This is useful to eliminate RFI (Radio Frequency Interference) and to prevent a large current from flowing to the load almost instantly. 

Solid State Relay Circuit 

The 25A - 110/220V Solid State Relay (SSR) Circuits using Triac BTA24-600 circuit diagram is shown in Figure 2 below. 

It uses a 25 Amp TRIAC BTA24-600, this is enough to handle loads up to a little over 5.500W, obviously using a isolated heat sink.
Fig. 2 - 25A - 110/220V Solid State Relay (SSR) Circuits using Triac BTA24-600

Basic Components Function

  • Diode D1, is used for reverse voltage protection, it inhibits reverse voltage. 
  • Resistor R1 of 240 ohm, limits the input current to the internal LED of the MOC
  • Resistor R2 of 330 ohms for 1W, it serves to limit the supply current to the MOC's internal DIAC.
  • Resistor R3 of 56 ohm, prevents any di/dt current when the TRIAC is off, eliminating false triggering. 

Components List

  • Semiconductors
    • Q1 .... BTA24-600 Triac
    • U1 .... MOC 3041 opto-isolator
    • D1 .... 1N4007 Diode

  • Resistor
    • R1 .... 240Ω (red, yellow, brown, gold)
    • R2 .... 330Ω (orange, orange, brown, gold)
    • R3 .... 56Ω (green, blue, black, gold
  • Miscellaneous 
    • P1, P2 .... 2-pin PCB soldering terminal blocks (Optional)
    • Others .... PCB, heat sink, wires, etc.

Printed Circuit Board

We are offering the PCB - Printed Circuit Board, in GERBER, PDF and PNG files, for you who want to do the most optimized assembly, either at home.

If you prefer in a company that develops the board, you can is downloading and make the files in the Download option below.
Fig. 3 - PCB - 25A - 110/220V Solid State Relay (SSR) Circuits using Triac BTA24-600

Files to Download, Direct Link:


If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.

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My Best Regards!!!