12W Amplifier Circuit Using 741 Op Amp Circuit Diagram

A 12 watt audio amplifier operating on a dual symmetrical supply of ± 12 volts. The 741 provides the required gain while the speaker drive is provided by the complementary Darlingtons T1, T2 and T3, T4.The input signals for the darlingtons are derived from the supply current of the 741. Since R6 is connected to the ground, the positive or negative signal currents also pass through R4 or R5. The voltage drop across these resistors serves as the input signal to the transistor pairs. An overall dc negative feedback from the common collector junction of T2 and T4 stabilises the dc conditions of the circuit and keeps the junction point at zero volts. Hence, no coupling capacitor is required for the speaker.

12W Amplifier Circuit Using 741 Op Amp Circuit Diagram

PARTS LIST
R1	10KΩ
R2	4.7KΩ
R3	270KΩ
R4	1KΩ
R5	1KΩ
R6	47Ω 1W
C1	50 Pf
C2	0.01 µF
T1	BC178
T2	2N6107
T3	AC108
T4	2N5294
IC	LM741
LS1	50W 4Ω

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