Band-Pass Filter (CB14921E)

This circuit was found in a Poptronics of the 90's. The components can be changed to the desired frequency. The power supply must be symmetrical.

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Unijunction AC Timed Switch (CB12289E)
In this circuit found in a 1991 publication we can use the 2N2646 unijunction transistor and the...
Microphone Impedance Matcher (CB4765E)
This microphone preamp allows the use of high impedance crystal microphones with amplifiers that have...
Integrated Circuit Transmitter (CB19453E)
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