Monday, May 24, 2021

Simple 100W Power Amplifier using TIP142 NPN and TIP147 PNP transistors + PCB

Fig 1 - PCB 100W Power Amplifier - TIP142 and TIP147 Transistors

This is a low complexity amplifier, which can be easily assembled by anyone who has basic knowledge in electronics.

This amplifier works with a Class B output stage with a complementary output pair formed by the TIP142 and TIP147 Darlington Transistors.


The input stage, is formed by a differential pair Q1 and Q2, which are two PNPs A733 transistors, the Q1 transistor receive the input signal for amplification, and Q2 receives the Feedback signal.

Thus assembling a signal loop making with the differential amplifier to control the signal giving stability to the amplifier and avoiding distortion in the circuit.

The second stage consists of a TIP41 transistor, which functions as a Drive, which receives the signal from the differential pair and amplifies it to delivery a sufficient current at the base of the output transistors.
This amplifier has an output power of approximately 100 watts, to get this output power will depend on the Power Supply voltage, with a supply voltage of + 50V / - 50V, with a current of 3A.

In our tests, it was possible to get a little more than 100W. The schematic diagram circuit, is in Figure 2 below, it is a very simple circuit to build, with few external components.

However, be careful, it works with a total voltage of 90V, be careful not to change any component polarity, don't short the amplifier circuit.
Fig 2 - Schematic Simple 100W Power Amplifier with  TIP142 NPN and TIP147 PNP transistors

Power supply

The power supply for this circuit amplifier is symmetrical, in our tests a Transformer with a +36V 0V -36V AC, center-tape was used, with a current 3 Amperes, after the CA voltage goes through the rectification, it will average 50V DC.

Components List

  • Semiconductor 
    • Q1, Q2 .... A733 - PNP transistor 
    • Q3 ........... TIP41C - NPN transistor
    • Q4 ........... TIP142 - NPN power transistor 
    • Q5 ............TIP147 - PNP power transistor 
    • D1, D2 .... 1N4007 - Diode 

  • Resistors 
    • R1, R2 ..... 22K ohms - 1/8W - Resistor  - (red, red, orange, gold)
    • R3 ........... 1K5 ohms - 1/8W - Resistor  - (brown, green, red, gold)
    • R4 ........... 220 ohms - 1/8W - Resistor  - (red, red, brown, gold)
    • R5 ........... 27K ohms - 1/8W - Resistor  - (red, violet, orange, gold)
    • R6 ........... 27 ohms - 1/8W - Resistor  - (red, violet, black, gold)
    • R7, R8 .... 3K3 ohms - 1W - Resistor  - (orange, orange, red, gold)
    • R9, R10 ... 022 ohms - 3W - Resistor  - (red, red, gold, silver)

  • Capacitors
    • C1 .......... 2.2uF - 25V - Electrolytic capacitor 
    • C2 .......... 100uF - 63V - Electrolytic capacitor 
    • C3 .......... 10uF - 63V - Electrolytic capacitor

  • Miscellaneous 
    • P1, P2 ..... Block 5mm 2 Pin weldable terminal Connector
    • P3 ........... Block 5mm 3 Pin weldable terminal Connector
    • Others .... Printed Circuit Board, Wires, Solders, Etc.

We are offering the PCI - 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.

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!!!

1 comment:

  1. Hola buenas tardes, armé el circuito y cuando le puse voltaje se quemó la resistencia de 27 ohm