How to Make a Simple Audio Amp

Audio amplifiers are used to replicate an alternating current (AC) audio signal and increase the voltage while maintaining the signal waveform. One simple type of audio amplifier is the Class A amplifier. This type of amplifier is used in audio amplification circuits that require a high-fidelity waveform, such as for guitar and musical amplifiers.<br /><br />Class A amplifiers often contain a single transistor and fewer than six resistors. Since there aren't many parts to the Class A amplifier, creating one can be a relatively simple affair.

Things You'll Need

• 2N2222 NPN transistor <br />3 resistors (10K ?)<br />100K ? resistor<br />12V power supply<br />2 ring terminals<br />Electrical wire<br />Electrical pliers<br />Soldering iron<br />Electronic (rosin core) solder

Instructions

1. Cut four lengths of wire, and strip the end of each wire of ½ inch of insulation. Slip a ring terminal over one of the ends of the first wire, and solder the terminal to the wire. Connect the other end of the first wire jointly to the Base transistor connection, one of the leads on the first 10K ? resistor and one of the leads on the second 10K ? resistor. Solder the electrical connection.

2. Connect the Emitter transistor lead to one of the leads on the third 10K ? resistor, and solder the connection. Connect the free lead of the second 10K ? resistor to the free lead on the third 10K ? resistor jointly to one end of the second wire. Solder the connection. Connect the free end of the second wire to the negative terminal on the power supply.

3. Connect one of the leads from the 100K ? resistor jointly to one end of the third wire and to the transistor Collector lead, and solder the connection. Slip the remaining ring terminal over the free end of the third wire, and solder the ring terminal to the wire.

4. Connect one end of the fourth wire jointly to the free leads of the 100K ? resistor and the first 10K ? resistor, and solder the connection. Connect the other end of the fourth wire to the positive terminal on the power supply.

References

• Electronics Tutorials: Class A Amplifier
• Elliott Sound Products: Simple Class A Amplifier; J. L. Linsley Hood, MIEE

Resources

• Radio Shack: MPS2222A Transistor