This circuit was obtained from an 80's Electronic Engineering. The circuit detects ice formation by triggering a warning light. The operational amplifier is of the time.
This effects circuit was found in a 1995 documentation. The circuit causes a sequence of LEDs to...
We found this circuit in a 1983 publication. It is a simple touch alarm circuit using a SCR type...
Found in an English publication from the 1980s, this circuit uses components that are still common...