This circuit is from a 1972 Motorola publication. The used transistor can still be found, but it can be used equivalent. The circuit is powered by the amplifier with which it must operate.
This 555 IC circuit was found in June 1984 Radio Electronics magazine. This circuit detects a...
We found this circuit in a 1976 publication for radio amateurs. It was originally intended for use in...
The integrated circuit used in this small transmitter is not very common today. The coil has its...