Simple class AB 1200 mw audio amplifier circuit designed by using IC HT82V739 from Holtek. This circuit requires only three external capacitors for its operation.
HT82V739 is a mono speaker driver IC available in 8pin package. Some of the important features of HT82V739 are listed, It requires only 2.2 V to 5.5 V single power source as a operating bias. Provides high signal to noise ratio with low distortion level. Consumes very low power for its operation. It can directly drive the speaker without coupling capacitor.
Circuit construction and Operation
Due to HT82V739 internal architecture, it requires few external capacitor elements. For input volume control use variable resistor (here we have used 20K variable resistor). Connect 8ohm loud speaker at the output pin, remember to connect speaker positive pin to OUTP pin and speaker negative pin to OUTN pin. If you’re using battery as power source then there is no need for C2 filter capacitor.
After completing the circuit construction apply 5 volt DC supply and apply audio signal input, then adjust the variable resistor to get proper output sound at the speaker.
This type of audio amplifier is best suitable for handheld devices and battery powered electronic devices.