Mini amplifier

Mini Amplifier



  Here is a simple project , mini amplifier built around LM1895 followed by passive components. The output of 10mW to 1W is obtained so, the circuit is called mini amplifier.

  The output from mike or pre-amplifier is fed to pin no.4 through variable resistor VR1 and capacitor C4. Variable resistor VR1 is used to select the intensity of signal. Capacitor C2 and C6 is used to filter and develop the supply, where capacitor C3 and C5 is used to bias the audio frequency. The output of amplifier IC is obtained at pin 1 where resistor R4 and capacitor C8 is used as feedback component. The output is given to loudspeaker through capacitor C7 in order to produce sound.

Parts List

Resistors (all ¼-watt, ± 5% Carbon unless stated otherwise)

R1 = 10 KΩ

R2 = 47Ω

R3 = 220Ω

R4 = 1Ω

VR1 = 50 KΩ

Capacitors

C1 = 470 pF

C2 = 220 µF/10V

C3 = 100 µF/10V

C4 = 0.1 µF

C5 = 10 µF/10V

C6, C7 = 470 µF/10V

C8 = 0.1 µF

Semiconductors

IC1 = LM1895N

Miscellaneous

LS1 = 4Ω/1W speaker