The integrated circuit used in this' 90s amplifier is not very common today. The supply is 24 V, the gain is 50dB and the input resistance is 100 k. The circuit is from an old circuit manual.
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...