This amplifier with the EL84 tube is a European commercial type from Corpim mounted on a printed circuit board. The diagram appeared in a September 1958 Radio Electronics magazine.
September 2016 - It can be purchased from Mouser Electornics the iW1818 of Dialog Semiconductor, a...
The figure shows how to increase the output current to about 50 mA of an operational amplifier. The...
This circuit locks after a short touch on the sensor. The circuit can be powered by voltages from 5...