This circuit applies to an old dial phone by detecting light pulses in the dial. The circuit is from an old 80's Electronic Design.
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...