20W Audio Amplifier is a 20W Hi-Fi mono amplifier using amplifier IC available at Rs 240/-. The IC TBA810 (IC1) which is an audio amplifier IC has been in production for several years. It has built in thermal and short circuit protection circuits, so it should have a reasonable life.
The main functions of IC are

• A. F. Preamplifier
• A. F. Driver
• A. F. Output

Without any additional cooling, the IC can deliver 1W into a 4W Loudspeaker with a 6V supply. With a sufficiently large cooling fin and a 16V supply it can deliver up to 20W into 4W. The input sensitivity in this case is 240mV. If 8W Loudspeaker are used, the maximum output power is about half.

The input impedance is practically determined by P1, so it is possible to connect a crystal cartridge direct to the input. If this high impedance is not required, the value of P1 can be reduced.
The frequency response is 3db from 40Hz to 18KHz. Note that the pin numbers in the circuit do not take account of the cooling fin; the IC has a total of 12 pins .The pin-out diagram is shown in figure.

20W Audio Amplifier is a 20W Hi-Fi mono amplifier using amplifier IC available at Rs 240/-. The IC TBA810 (IC1) which is an audio amplifier IC has been in production for several years. It has built in thermal and short circuit protection circuits, so it should have a reasonable life.
The main functions of IC are

• A. F. Preamplifier
• A. F. Driver
• A. F. Output

Without any additional cooling, the IC can deliver 1W into a 4W Loudspeaker with a 6V supply. With a sufficiently large cooling fin and a 16V supply it can deliver up to 20W into 4W. The input sensitivity in this case is 240mV. If 8W Loudspeaker are used, the maximum output power is about half.

The input impedance is practically determined by P1, so it is possible to connect a crystal cartridge direct to the input. If this high impedance is not required, the value of P1 can be reduced.
The frequency response is 3db from 40Hz to 18KHz. Note that the pin numbers in the circuit do not take account of the cooling fin; the IC has a total of 12 pins .The pin-out diagram is shown in figure.