Found in a 1964 Electronic Design, this circuit makes use of FETs of the time. These transistors can be replaced by modern general-purpose types. The input resistance is 30 M.
This circuit was found in a Mullard transistor manual from 1960. Note the symmetrical power...
With the shadow over the sensor, it is possible to interrupt the sound of your amplifier using this...
This circuit puts the battery in the circuit when the voltage of a source is cut, preventing it...