For the 1 MHz frequency, the pass band of this filter is only 120 Hz wide. The filter is suitable for telecom applications and its impedance is 600 ohms.
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...