Suggested by a 90s EDN, this circuit supports almost any LED as a source and a phototransistor as a detector. The circuit operates with a PLL 567 at a frequency of around 40 kHz.
This TTL circuit was found in the December 1990 issue of Radio Electronics magazine. The circuit has...
We found this circuit in Sperimentare magazine number 4 of 1977. The magazine no longer exists, but...
This crystal configuration can be made with triggers of any logic. The frequency is given by the...