This circuit is from a 1977 Radio Shack manual. The photocell is an LDR and the operational one is a 741. Components with non-standard values can be approximated.
Found in a1967 Ferranti documentation, this circuit uses an operational amplifier from that time....
May 2017 - ROHM is announcing the availability through Mouser Electronics of a broad line of fast...
This circuit was adapted from an Italian publication that no longer exists. This is “Onda Quadra”...