This circuit that can amplify signals from 0 to 30 MHz was found in a 90s Popular Electronics. Transistors admit current equivalents. The input impedance is high.
This small general purpose and RF transistor tester appeared in a February 1958 Radio Electronics...
The MC4741 integrated circuit consists of four operational amplifiers similar to the 741 in a...
We found this touch control on a Popular Electronics from 1970. The circuit makes use of an...