Source follower (CB6963E)

Found in American documentation, this circuit shows how to polarize a FET in bootstrap mode. The circuit applies to any FET.

Sensor for heart monitor (CB21075E)
We found this heart rate sensor circuit in a Popular Electronics from the 90s. The placement of...
Active cycle meter (CB7072E)
Based on an LM317T, this circuit found in Popular Electronics works with signals of frequencies up to...
0.01 Hz to 100 MHz amplifier (CB13396E)
The circuit shown is from a 1972 publication. Transistors can be current types like 2N2222. The...