INTRODUCTION
• It is a simple audio amplifier.
• It is a low voltage power amplifier
• It amplifies audio signal to some extent.
• The heart of this amplifier is IC LM386.
• Input is given through phone or pc.
CIRCUIT DIAGRAM
Component used
Sr.no Name Value
1. IC LM386
2. Capacitors 100,200
micro farad
3. Capacitors 0.01,0.047
(Ceramic)
4. Resistors 5kilo
ohm,100,1
0 ohm
5. Power 12v,5v
supply
6. Stereo jack 3.5mm
7. Copper 1
clad
8. Speaker 8ohm
IC LM386
IC LM 386 is a low power audio amplifier integrated circuit.
It is an 8 pin IC.
In this amplifier only 7 pins are used.
This IC operates on 9v supply.
This supply is given to pin number 6.
4th pin is always connected to ground
PIN CONFIGURETION
ELECTROLYTIC CAPACITOR
An electrolytic capacitor is a type of capacitor that uses an
electrolyte to achieve a larger capacitance than other
capacitor types.
The voltage on the positive,
Terminal must always b greater than the voltage on the
negative
CERAMIC CAPACITOR
• A ceramic capacitor or disc capacitor a fixed value capacitor
in which ceramic material acts as the dielectric.
• Some applications of single layer ceramic capacitors
Are:-
• Temperature compensation.
• Coupling and decoupling applications
• AC power supply and filter applications
• Bypassing applications
• Resonant circuit applications
RESISTORS
• There are many types of resistors, both fixed and variable.
The most common types for electronics use is the carbon
resistor. They are made in different physical sizes. The resister
value and tolerance determined from the standard resistor
color code.
WORKING
The signal to be amplified is coupled through a male 3.5 mm
connector and then the signal fed to the input pin of LM 386.
After that the internal circuits of IC amplifies the level of signal
and then gives the output at pin number 5. The output signal is
then pass through the 220 microfarad capacitor and then the
signal goes to output by passing through a variable resistor. By
varying the value of resistor the level of volume can be
controlled. Then the output is fed to the speaker.
Advantages
This is a low voltage power amplifier according to its
amplification factor it has some advantages as follows:-
• The circuit of this amplifier is not so much complex so it is
easy to make it.
• This amplifier circuit uses capacitor and resistor and an IC,
due to this the cost is very low.
• By doing the proper matching of impedance a medium output
can obtained.
• The reliability of this audio amplifier is also high.
Disadvantages
• The level of output is not that much high. To obtain high
output multistage may be required.
• The quality of sound is also low.
• There is some amount of noise present in the final output.
Applications
• These are required in function, competitions, parties,
speeches etc.
• Audio amplifiers are used in devices like TV, Radio etc.
• It can be used to listen songs in a single room.
