The indicator for this circuit is a 0 to 1 mA milliammeter. The operational is from the 70s, when the circuit was published. Modern equivalent can be used.
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...