Found in a 1947 publication, this circuit uses 4 parallel/push-pull tuber in the output stage. The circuit employs dual power supply with two rectifier tubes.
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...