LED Flasher Unijunction (CB22144E)

The frequency of this circuit depends on the capacitor. The unijunction transistor can be the 2N2646.

200 Hz to 400 Hz Band Pass Filter (CB13603E)
We found this circuit in a 1975 filter cookbook. The circuit can use other operational amplifiers and...
Guitar Intensifier (CB11507E)
The purpose of this circuit found in a Popular Electronics from 1972 is to intensify certain...
Mini MW Transmitter (CB10307E)
This circuit was found in a 1964 magazine, which no longer exists. It is a small wireless...