This circuit was found in the June 1991 issue of Radio Electronics magazine. The circuit uses two Hall effect sensors of the time. It can be assembled using modern equivalents.
This circuit is a wireless temperature transmitter for RF signals in the range of 0.2 to 2 MHz...
We found this circuit in an old Radio Electronics. Components can be replaced by modern...
This immobilizer circuit for vehicles was found in a 80’s Hands On Electronics. The circuit...