In this tutorial, we are going to make a “1200 mw Audio Amplifier Circuit”.
An audio amplifier is an electronic amplifier that amplifies low-power electronic audio signals such as the signal from a radio receiver or electric guitar pickup to a level that is high enough for driving loudspeakers or headphones. We design a simple class AB 1200 MW audio amplifier circuit by using IC HT82V739 from Holtek. HT82V739 is an amplifier that only makes the sound. It’s a mono speaker driver IC available in an 8pin package.
Some of the important features of HT82V739 are listed, it requires only a 2.2 V to 5.5 V single power source as an operating bias. Provides a high signal-to-noise ratio with a low distortion level. Consumes very low power for its operation. Has a low standby current and power-off control. It can directly drive the speaker without a coupling capacitor.
Hardware Components
The following components are required to make Audio Amplifier Circuit
| S.no | Components | Value | Qty |
|---|---|---|---|
| 1. | Electrolyte Capacitor | 1uF,47uF | 1, 1 |
| 2. | Ceramic capacitor | 1uF | 1 |
| 3. | IC | HT82V739 | 1 |
| 4. | Variable Resistor | 20K | 1 |
| 5. | Speaker | – | 1 |
HT82V739 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of HT82V739
Audio Amplifier Circuit
Working Explanation
This circuit requires few external capacitors for its operation due to HT82V739 internal architecture. Here we need three external capacitors. Now we have a variable resistor, which is used to control input volume (here we have used a 20K variable resistor). Then connect the 8ohm loudspeaker at the output pin, remember to connect the speaker positive pin to the OUTP pin and the speaker negative pin to the OUT pin. If you’re using a battery as a power source then there is no need for a C2 filter capacitor. As soon as completing the circuit construction apply audio signal input and apply a 5 volt DC supply, finally adjust the variable resistor to get proper output sound at the speaker.
Applications
This type of audio amplifier is best suitable for handheld devices and battery-powered electronic devices.
