The pentode tube used in this circuit has 1.5 V filament. The circuit is a voltage amplifier with the 1U5 tube.
This is a multi-component tester with visual indication by LED and polarity selection in the test....
This circuit is from a 1978 operational amplifier manual. The power supply must be symmetrical, and the...
This circuit is stabilized by a thermistor or NTC with a resistance between 2 and 5k. The signal is...