This circuit was obtained in an American documentation from the 80's. The transistors can be equivalent to those indicated and the crystal can reach a few tens of megahertz.
Found in a 1967 Electronic Design, this circuit can detect pulses as narrow as 0.2 us. Active...
We found this circuit in the May 1970 issue of Radio Electronics magazine. The maximum frequency...
This flasher was found in the September 1984 Radio Electronics magazine. The frequency is given by...