We found this circuit in a 1987 documentation. It is a multi-tester with neon lamp and LEDs operating with both low continuous voltage and high alternating voltage.
In the figure we have the diagram of an amplifier stage using transistor and a 6AQ5 valve. The...
Being able to operate with frequencies up to 100 kHz, this circuit was found in a 90’s...
This circuit immobilizes a car with an old ignition system with platinum switches. It was found in the...