Poor Man's Electronics Web Page

One Transistor Audio Amp

Using the amplifier:

crystal set + amp
One transistor audio amp connected to a crystal radio

Connect the amplifier to the crystal radio project. I used a small length of shielded cable from the amplifiers input and ground connections to the "phone" terminals of the radio. It doesn't have to be shield cable, any two wires will work in this case. For high gain amplifiers; however, it is a good practice to use shielded cable to reduce noise and hum pick up.

I used 2000 ohm military headphones as shown in the picture above connected to the output and ground connections of the amp. The ceramic type earphones will work also. In fact, even a small speaker will work.

Turn the amplifier switch on. Tune the radio. You may find the local stations to be very loud, even to the point of distortion. If so, reduce the size of the 330uuF trimmer capacitor in the crystal radio until you get a good listening volume and selectivity trade-off. At night, you can DX the broadcast band with this set up. (DX is the radio enthusiasts term for "Distance Reception".)

Copyright © 2007 - Prof. W.S. Walker, West Virginia State University - All Rights Reserved.
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