In this circuit, which uses only diodes, we have both simultaneous functions. The diodes are general-purpose types and the resistors have typical values of 2k2.
I got this circuit from an English magazine from 1977. It can still be easily assembled, as the...
This simple lie detector was found in Popular Electronics. Transistors are commonly used. The...
Found in a 1980 documentation, this circuit drives a transducer (X1) when the car battery has its...