60W inverter using transistors

Here is the circuit diagram of a fully transistorized inverter that can drive up to 60W loads. Transistors Q1 and Q2 forms a 50Hz astable multivibrator. The output from the collector of Q2 is connected to the input of the Darlington pair formed by Q3 and Q4.Similarly the output of Q1 is coupled to the input of the pair Q5 and Q6. The output from the Darlington pairs drive the final output transistors Q7 and Q8 which are wired in the push pull configuration to drive the output transformer.

Circuit diagram.

Notes.

The circuit can be assembled on a vero board.

T1 can be a 230V primary to 9-0-9V, 6A secondary transformer.

Transistors Q4, Q6, Q7 and Q8 must be fitted with heat sinks.

Use a 12V, 7Ah battery for powering the inverter.

Slight adjustments can be made on the value of R3 and R4 to get exact 50Hz output.

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Build a 60W Transistored Power Amplifier Circuit Diagram

This is the circuit diagram of 60W transistored power amplifier. This circuit was designed and built during the 80s. From then it works without problem. It does not present a particular construction problem, apart from the known: the attention to the supplied power source, choosing suitable heatsinks and good matching of the driver transistors. The diodes D3..5 should be placed on the heatsinks of power transistors to have thermal coupling with the output transistors.

 60W Transistored Power Amplifier Circuit Diagram

With the trimmer R15, we regulate the voltage at the output of the amplifier [with long work hours and little heat stabilized]. With the trimmer TR1, we can adjust the bias current of the amplifier at 50 to 100 mA. The bias current can be measured if you measure the voltage drop at the ends of the resistors R36 and R37, for the voltage that are given in the circuit, the current is approximately 75 mA. The voltage indicated in above diagram can be different, but may have a tolerance of about +/- 10%.

Parts List

R1 = 1.8K ohm	R25 = 8.2K ohm	D1,D2 = 24V/1W Zener	C1 = 4.7uF/25V
R2 = 220K ohm	R26 = 27K ohm	D3….9 = 1N4002	C2 = 470pF
R3 = 27K ohm	R27 = 820 ohm	T1-2 = BC550C	C3-4 = 100uF/63V
R4,R10,R11,R17 = 3.3K ohm	R28 = 3.3K ohm	T3,T4 = BC560C	C5 = 68pF
R5,R9,R12,R16 = 100 ohm	R29 = 100 ohm	T5,T13 = BD530	C6,C10 = 330pF
R6 = 18K ohm	R31,R39 = 180 ohm	T6,T8 = BC414C	C7 = 22pF
R7,R13 = 3.9K ohm	R32,R38 = 6.8K ohm	?9 = BC416C	C8 = 220uF/16V
R14 = 10K ohm	R33,R34 = 1.2K ohm	T7,T10 = BD529	C9 = 100nF 100V
R15 = 22K ohm Trimmer	R35 = 82 ohm /1W	T11 = BD591	C11,C12 = 10pF
R18,R23 = 330 ohm	R36,R37 = 0.33 ohm / 5W	T14 = BD592	C13,R15 = 47uF/63V
R19,R21,R22 = 15K ohm	R40,R41 = 10 ohm / 2W	T12 = 2N5630	C16,R17 = 100nF/100V
R20 = 12K ohm	R42 = 180 ohm/5W	T15 = 2N6030	C18,R19 = 100nF/100V
R24,R30 = 82 ohm	TR1 = 4.7K ohm Trimmer

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STK4038 60W Amplifier Circuit

STK4038 is an built in AF power amplifier that will deliver 60 watts of output power into a 4 ohm load. The internal fixed current circuitry reduces switch ON/OFF clicks. The IC supports the addition of external circuits for thermal shutdown, pop noise reduction, output short circuit protection etc.

The 60 watt amplifier is designed Depending about the datasheet and performs incredibly well. Capacitor C1 is the input DC decoupling capacitor Which blocks any DC level present at the audio input and C12 is the input by-pass capacitor. R1 is the input resistor.

C10 and C8 seem like the ripple filter capacitors in to the certain and negative power supply rails. R9 and R7 seem like the current limiting resistors in to the internal driver stage although C11 and C3 seem like their corresponding filter capacitors. Resistor R6 feeds back a portion of those output signal in to the inverting input (pin2). Gain these amplifier depends about the value of R6. C9 and R2 forms a Zobel network Which improves the high frequency stability of those amplifier.

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