Found in a 1968 American documentation, this circuit uses an operational amplifier that is uncommon today. The feed must be symmetrical. The gain is 40 dB.
This high quality circuit with complementary symmetry was found in an Electronics World of 1966....
Found in an Electronic Design this circuit controls a headlamp by triggering a time determined by the...
This small switched regulator was found in an 60’s Optical Electronics. The circuit uses an...