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 is a typical symmetrical power supply configuration. The transformer voltage determines the...
This circuit triggers at the touch of the sensor, passing its output from high to low level for a...
The traditional circuit was taken from a French magazine Radio Plans that no longer exists but can...