Amplifier stage with the T411E (T411E)

The pentode tube used in this circuit has 1.5 V filament. The circuit is a voltage amplifier with the 1U5 tube.

Automatic Battery Charger (CB10565E)
This circuit is from a 1987 magazine, but it can still be easily assembled, as the components are...
Bargraph Humidity Indicator (CB11519E)
This circuit was found in a Popular Electronics from 1991. The transistor could be the BC548. The...
Capacitive Differential Meter (CB9493E)
This circuit, which can be used to indicate the movement of an object, was found in NASA...