This circuit is from a Hands-On Electronics from the 90s. The integrated amplifiers used are well known. The range is a few tens of meters depending on the resistance of the cables.
Passaje Alarm This locking circuit was found in a 1988 publication. It locks a relay when the...
This windshield wiper interval switch was found in the April 1990 issue of Radio Electronics...
Found in a 2005 Linear Technology application manual, this circuit monitors the current in a load...