This circuit is from documentation from 1965 but can be easily implemented today using modern transistors. We can use BD136 for Q1 and TIP42 for Q2. The TIP must be equipped with a heat sink.
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...