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 simple lie detector was found in Popular Electronics. Transistors are commonly used. The...
Found in documentation from the 1980s, this circuit uses an operational amplifier from that time....
This circuit allows the detection of RF signals using the lowest range of direct currents of a...