Originally this circuit was created to produce synchronism pulses in TV cameras SSTV (Low scan frequency), however it can be adapted for other purposes. The integrated circuits are common TTL.
We found this protection circuit for the power supply in a 1992 documentation. This circuit has...
I found this circuit in a documentation for radio amateurs from 1975. The FET could be the BF245....
Found in an American 80's documentation, this circuit can use common FETs like the BF245 and cover...