This circuit is from an old American publication, using transistors of the time and operating with a 48 V power source. The load is 2.2 ohm, and the transistors must be replaced by modern equivalents.
Found in a 1967 American publication, this circuit with feedback for two transistors has a gain of...
This simple 5.6 V regulator circuit was found in a 1966’s Philips. The zener can be changed to...
This small amplifier with a low impedance microphone that can be used for hearing aid was found in a...