Found in Popular Electronics from the 90s, this circuit detects modulated infrared radiation and serves as a test for remote controls. Infrared sensors equivalent to the one indicated can be used.
This squelch is activated by its own noise, acting automatically. It is used in communications...
This circuit for a simple alarm system was suggested in an article in Electronics Now magazine. The...
Found in American documentation from the 70s, this circuit uses components of the time, uncommon...