Suggested by an American publication of 1964 this circuit is intended for the capture of signals from film tracks recorded by optical systems, common at the time.
Found in a 90s Electronic Design, this circuit is used with a 9 V adapter for powering small...
Found in a 1990s Electronics Now, this circuit is designed for signals up to a few megahertz....
With S1 closed, when dark, the triac will supply the load with the power set in R4. The LDR is...