Fig, 1 - 12 Volts Automatic Lead Acid Battery Charger Circuit + PCB

This is a 12V Automatic Lead Acid Battery Charger Circuit, of the type used in nobreaks, with loads ranging from 1A to 9 Amps.

What is Lead Acid Battery

Lead Acid Battery Charger Method

There are several features related to the charging process of various battery segments and classes. 

The charging method for lead-acid batteries differs from NiCd batteries in the voltage limit, rather than the current limit to be used.

The charging time for lead-acid (sealed) batteries is 8 to 16 hours, depending on the capacity of the battery and the method used. 

With higher charging currents and multi-stage charging methods, the charging time can be reduced to 8 hours or less. 

For a multi-stage charger, three stages of charging application are required: 

•  Constant current
•  Peak charge
•  Float charge
  
  

The Circuit

In Figure 2 below, we have the schematic diagram of the lead-acid battery charger circuit. It is a very simple circuit, with few external components, easy to assemble, yet even with its simplicity it works very well.

Fig. 2 - Schematic Circuit 12 Volts Automatic Lead Acid Battery Charger Circuit

Working

The voltage regulation for charging the battery is done by the LM350 IC voltage regulator. 

The charging current control is done using the BC548B NPN transistor, it controls the demand current from the battery, causing the circuit to activate or deactivate the voltage required for charging the battery.

The potentiometer RP1 1K is used for fine tuning the battery charging voltage, which should be adjusted by using a multimeter to measure the output voltage, which should be at most 20% of the nominal battery voltage.

If you cannot find the description of the battery charging voltage on the battery itself, you can adjust the average charging voltage, which ranges from 13.8V to 14.4V.

It is necessary to use a heat sink in the voltage regulator, since the initial current to charge the battery is high. 

As the circuit charges the battery, it lowers the charging current until it reaches zero voltage, when the battery is fully charged.

Components List

• Semiconductors
• U1 .......... LM350 Voltage Regulator Circuit
• Q1 .......... BC548B NPN Transistor
• D1 .......... 1N5408 Silico Diode
  
  
• Resistor
• R1 .......... 100Ω Resistor (brown, black, brown, gold)
• R2 .......... 0.5Ω 5W Resistor (green, black, silver, gold) 
• R3 .......... 470Ω Resistor (yellow, violet, brown, gold)
• R4 .......... 120Ω Resistor (brown, red, brown, gold)
• RP1 ........ 1KΩ Potentiometer
  
  
• Capacitor
• C1 .......... 2.2uF / 25V Electrolytic Capacitor
• C2 .......... 0.33uF / 25V Electrolytic Capacitor
   
• Other
• P1, P2 .... 2-pin PCB soldering terminal blocks
• Others .... Printed Circuit Board, Heat Sink, tin, wires, etc.

Printed Circuit Board

In Figure 3, we provide the PCB - Printed Circuit Board, in GERBER, PDF and PNG files. These files are available for free download, on the MEGA server, in a direct link, without any bypass. 

All to make it easier for you to do a more optimized assembly, either at home, or with a company that prints the board. You can download the files in the Download option below.

Fig. 3 - PCB - 12 Volts Automatic Lead Acid Battery Charger Circuit

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.

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My Best Regards!!!

Fig. 1 - 14.4V, 70W High Efficiency Power Amplifier using TDA1562Q IC + PCB

The original project: Click Here!

This is a high efficiency and high power amplifier, powered by a simple 14.4V power supply, can provide a power of 70W in 4Ω, using the TDA1562Q Integrated Circuit.

Features

• Very high output power, operating from a single low supply voltage
• Low power dissipation, when used for music signals
• Switches to low output power at too high case temperatures
• Few external components
• Fixed gain
• Differential inputs with high common mode rejection
• Mode select pin (on, mute and standby)
• Status I/O pin (class-H, class-B and fast mute)
• All switching levels with hysteresis
• Diagnostic pin with information about:–  Dynamic Distortion Detector (DDD)–  Any short-circuit at outputs–  Open load detector–  Temperature protection.
• No switch-on or switch-off plops
  
  

You might also be interested in:

• 24W Stereo Hi-Fi Audio Amplifier using TDA2616 + PCB
• 68W Hi-Fi Audio Power Amplifier using LM3886T IC + PCB
• 4 x 50W High Power Amplifier, 14.4V - IC TDA7563A + PCB
• 320W Power Audio Amplifier, Powered with 14.4V - 2Ω with IC TDA7560 + PCB
• 100W RMS Audio Amplifier IC TDA7294 + PCB
• 200W RMS Stereo Power Amplifier with IC STK4231II + PCB
  
  

The Schematic

In Figure 2 below we have the schematic diagram of the High Efficiency Power Amplifier circuit and we can follow and analyze all the simplicity of the circuit, and as we can see, it is a circuit of easy assembly, and with few external components.

Fig. 2 - Schematic 14.4V, 70W High Efficiency Power Amplifier using TDA1562Q IC

Power Supply

This amplifier is powered by a simple positive and negative voltage type power supply, and has a supply voltage range that varies with a minimum voltage of 8V and a maximum voltage of 18V, the typical unstressed working voltage of the Integrated Circuit is 14.4V. 

The power supply should have a current of at least 5 Amperes, to be used in mono mode, if mounting in the stereo, "two channel" version, the current should be doubled, and should also be provided with good filtering to avoid ripples in the system, which can cause noise in the amplifier.

The impedance of this amplifier to reach its full power is 4Ω, however we can set it to 8Ω, however we will not get the maximum power of the amplifier.

Component List

• Semiconductors
• CI1 ............ TDA1562Q Integrated Circuit 
• LD1 ........... LED Light Emitting Diode
  
  
• Resistors
• R1 .............. 1MΩ resistor (brown, black, green, gold)
• R2 .............. 10KΩ resistor (brown, black, orange, gold) 
• R3 .............. 5.6KΩ resistor (green, blue, orange, gold)  
  
  
• Capacitors
• C1, C2 ....... 470nF Ceramic / Polyester Capacitor
• C3 .............. 10uF / 63v Electrolytic Capacitor
• C4, C5 ....... 4700uF / 25V Electrolytic Capacitor
• C6 .............. 100nF Ceramic / Polyester Capacitor
• C7 .............. 2.200uF / 25V Electrolytic Capacitor
  
  
• Others
• P1, P2, P3 ... Screw Terminal Type 5mm 2-Pin Connector
• Others ......... Heat sink for IC, wires, connectors, PCB, tin etc.

Printed Circuit Board

In Figure 3, we provide the PCB - Printed Circuit Board, in GERBER, PDF and PNG files. These files are available for free download, on the MEGA server, in a direct link, without any bypass. 

All to make it easier for you to do a more optimized assembly, either at home, or with a company that prints the board. You can download the files in the Download option below.

Fig. 3 -  PCB 14.4V, 70W High Efficiency Power Amplifier using TDA1562Q IC

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!!!

Fig. 1 - 170W AB Class Bridge Mode Amplifier using TDA7294 IC + PCB

This is a Class AB Audio Power Amplifier, it uses two TDA7294 Integrated Circuits, in Bridge Mode to drive one or more power speakers.

The circuit provides a total output power of 170W, and this with good sound quality, powered from a symmetrical power supply.

The Amplifier responds very well to all audible frequency ranges, and has a minimalist, compact design, which makes this amplifier a good choice for an unprecedented range of application. 

IC Description

The TDA7294 is  a monolithic integrated circuit in Multiwatt15  package, intended  for  use  as  audio class   AB   amplifier   in   Hi-Fi   field   applications (Home Stereo, self powered loudspeakers, guitar amplifier, Top-class TV). 

Thanks to the wide voltage range and to the high out current capability it is able to supply the highest power into both 4Ω and 8Ω loads even in  presence of  poor supply regulation, with high Supply Voltage Rejection.

The  built  in  muting  function  with  turn  on  delay simplifies the remote operation avoiding switching on-off noises.

You might also be interested in:

• 24W Stereo Hi-Fi Audio Amplifier using TDA2616 + PCB
• 68W Hi-Fi Audio Power Amplifier using LM3886T IC + PCB
• 4 x 50W High Power Amplifier, 14.4V - IC TDA7563A + PCB
• 320W Power Audio Amplifier, Powered with 14.4V - 2Ω with IC TDA7560 + PCB
• 100W RMS Audio Amplifier IC TDA7294 + PCB
• 200W RMS Stereo Power Amplifier with IC STK4231II + PCB
  
  

The main Advantages offered by Bridge solution

• High power performance with voltage level limiting supply.
• Considerably high output power, even at high load values (i.e. 16 Ohm).
• For a Speaker with 8Ω, Vs = ± 25V, the maximum output power obtained is 150 W, while with a Speaker with 16Ω, Vs = ± 35V, the maximum power is 170 W.

Features

• Operating Voltage Range (± 10V to ±40V)
• DMOS Output Stage
• High Output Power (Up to 100W musical)
• Muting / Stand-By Functions
• No Switch On/Off Noise
• No Boucherot Cells
• Very Low Distortion
• Very Low noise 
• Short-circuit protection
• Thermal shutdown
  
  

Bridge Application

Our amplifier is configured in Bridge mode, where two TDA7294s ICs are used. With this type of configuration we get a pretty significant 170W of power, however there are two different configurations: 

For 16Ω Speaker - Vs = ± 35V, the maximum power is 170 W.

We know that the TDA7294, supports 4Ω or 8Ω speakers in mono version, however, for this application in Bridged configuration, the speaker impedance shouldn't be less than 8Ω for reasons of dissipation and current carrying capacity of the Integrated Circuits.

The Schematic Circuit

In Figure 2 below we have the arrangement of the components of the amplifier circuit with the two TDA7294 ICs, and as we can see, the difficulty is not extreme.

Since there are few external components, making the amplifier circuit very simple to assemble, and a technician or hobbyist with average experience can assemble it without much difficulty. 

It is important to remember to be careful when assembling the circuit, not to invert any component such as capacitor diodes, or even when connecting the symmetrical voltage of the power supply.

Not to invert the voltage poles, because the integrated circuit or other components can be damaged.

Fig. 2 - Schematic 170W Amplifier Circuit in Bridge with Integrated Circuit TDA7294

Components List

• Semiconductors
• U1, U2 ........................ TDA7294 Integrated Circuit 
• D1 ............................... 1N4148 Silicon Diode
  
  
• Resistors
• R1, R5, R6, R8, R10 ... 22K Resistor (red, red, orange, gold)
• R2 ................................ 20K resistor (red, black, orange, gold)
• R3 ................................ 10K resistor (brown, black, orange, gold)
• R4 ................................ 30K resistor (orange, black, orange, gold)
• R7, R9 ......................... 680Ω resistor (blue, gray, black, gold)
  
  
• Capacitors

• C1, C4 ......................... 1μF Ceramic/Polyester Capacitor
• C2, C3, C5, C6 ............ 22μF Electrolytic Capacitor
  
  
• Others
• P1, P2 ......................... Screw Terminal Type 5mm 2-Pin Connector
• P3 ................................ Screw Terminal Type 5mm 3-Pin Connector
• J1 .................................Set of male connectors 3-Pin (Optional)
• Other ........................... PCB, Wires, Speaker, etc.
  
  

Power Supply

The power supply will depend on which output power you will choose, which will also depend on how many Ohms your speaker will have. We have two versions:

Version 1 - 150W output.

• Speaker must be 8Ω and the maximum voltage is for ±25V

Version 2 - 170W output.

• Speaker must be 16Ω and the maximum voltage is ±35V.

Remember that for both versions a Symmetrical power supply is used, i.e. [ +VCC | GND | -VCC ]. With a current of at least 6 Amperes.

Printed Circuit Board

In Figure 3, we provide the PCB - Printed Circuit Board, in GERBER, PDF and PNG files. These files are available for free download, on the MEGA server, in a direct link, without any bypass. 

All to make it easier for you to do a more optimized assembly, either at home, or with a company that prints the board. You can download the files in the Download option below.

Fig. - PCB 170W AB Class Bridge Mode Amplifier using TDA7294 IC

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!!!

Fig. 1 - HI-FI 120W RMS Amplifier Circuit using LM4780 IC

This is a HI-FI Audio Amplifier circuit with high quality with a large frequency response, using the Integrated Circuit LM4780 which is a stereo audio amplifier. 

Capable of providing normally 60W per channel of average power of continuous output on an 8Ω load with less than 0.5% THD + N from 20Hz to 20kHz.

LM4780 General Description

The LM4780 is fully protected utilizing National’s Self Peak Instantaneous Temperature (˚Ke) (SPiKeTM) protection circuitry. 

SPiKe provides a dynamically optimized Safe Operating Area (SOA). SPiKe protection completely safeguards the LM4780’s outputs against over-voltage, under-voltage, overloads, shorts to the supplies or GND, thermal runaway and instantaneous temperature peaks. 

The advanced protection features of the LM4780 places it in a class above discrete and hybrid amplifiers.

Each amplifier of the LM4780 has an independent smooth transition fade-in/out mute. The LM4780 can easily be configured for bridge or parallel operation for 120W mono solutions.

Key Specifications

• Output Power/Channel with 0.5% THD+N, 1kHz into 8Ω 60W (typ)
• THD+N at 2 x 30W into 8Ω (20Hz - 20kHz) 0.03% (typ)
• THD+N at 2 x 30W into 6Ω (20Hz - 20kHz) 0.05% (typ)
• THD+N at 2 x 30W into 4Ω (20Hz - 20kHz) 0.07% (typ)
• Mute Attenuation 110dB (typ)
• PSRR 85dB (min)
• Slew Rate 19V/µs (typ
  
  

The Circuit

In Figure 2 below, we have the arrangement of the amplifier circuit components with the LM4780 IC, and as we can see, there are few external components. 

It is making the amplifier circuit very simple to assemble, one must be careful when assembling the circuit, so as not to invert any component, as it may suffer circuit burnout.

Fig. 2 - Schematic diagram of Hi-Fi Amplifier 120W RMS with IC LM4780

Features

• SPiKe protection
• Few external components
• Silent fade-in / mute out mode
• Wide range of supply voltage: 20V - 84V
• Signal-to-noise ratio ≥ 97dB (ref. for PO = 1W)
  
  

Power Supply

The power supply is a +-35V symmetric power supply. If you want to use it in stereo mode with two channels, it will be necessary to use twice the current to support the power of 240W, 120W per channel.

The power supply must have a good filter to avoid roaring, interference, and oscillations in the amplifier output.

The consumption current for a channel "One integrated circuit", must be 4 amps, if using two circuits, in stereo mode, the current must be doubled, in this case 8 amps.

The LM4780 must be equipped with a heatsink, if you use the IC without the heatsink, it will burn out.

It is recommended to tinker the voltage and output tracks, since the IC has a tight pinout, making it impossible to widen the tracks on the PCB.

Component List

• Semiconductors
• U1 ........................ Integrated Circuit LM4780
  
  
• Capacitors
• C1 ........................ 1uF Polyester / Ceramic Capacitor
• C2 ........................ 4.7uF - 50V Electrolytic Capacitor
• C3, C5, C8, C9 ... 0.1uF Polyester / Ceramic Capacitor
• C4 ........................ 4.7uF Polyester / Ceramic Capacitor
• C6, C7 ................. 47uF - 50V Electrolytic Capacitor
  
  
• Resistors:   
• R1, R6, R7 .......... 47k ohm resistor - (yellow, violet, orang, gold)
• R2 ....................... 10k ohm resistor - (brown, black, orange, gold)
• R3, R5 ................ 4.7k ohm resistor - (yellow, violet, red, gold)
• R4 ....................... 3.3k ohm resistor - (orange, orange, red, gold)
• R8, R9 ................ 2.7 ohm resistor - (red, violet, red, gold)
  
  
• Others
• SW1 ................... Switch on/off - to mute "optional"
• P1, P2 ................. Screw Terminal Type 5mm 2-Pin Connector
• P3 ....................... Screw Terminal Type 5mm 3-Pin Connector
• PCB, Wires, Solders, Speaker and Etc.
  
  

In Figure 4, we provide the PCB - Printed Circuit Board, in GERBER, PDF and PNG files. These files are available for free download, on the MEGA server, in a direct link, without any bypass. 

All to make it easier for you to do a more optimized assembly, either at home, or with a company that prints the board. You can download the files in the Download option below.

Fig. 3 - PCB HI-FI 120W RMS Amplifier Circuit using LM4780 IC

Files to Download, Direct Link: