Bridge Power Audio Amplifier

Here is simple circuit of bridge power audio amplifier used in application requiring more power than is provided by the single LM380 amplifier, the two LM380s can be used in the bridge configuration shown in figure 1. In this arrangement (bridge power audio amplifier) the maximum output voltage swing will be twice that of a single LM380 amplifier; therefore, the power delivered to the load by bridge power audio amplifier will be four times as much. For improved performance, potentiometer R₃ should be used to balance the output offset voltage of the LM380s. Here R₂ C₃ for stability with high-current loads.

 

Resistors (all ¼-watt, ± 5% Carbon)

R₁ =2 MΩ potentiometer

R₂ = 2.7 Ω

R₃ = 1 MΩ

Capacitors

C₁, C₂, C₃ = 0.1 µF

C₄ = 51 pF

Semiconductors

IC₁, IC­₂ = LM380 audio power amplifier

Miscellaneous

8Ω 1-W speaker