This sequential relay actuation system circuit for traffic lights was found in Electronics Now from the 1990s. Relays are sensitive types of low current coil.
Found in a 1967 EEE, this circuit oscillates at 20 MHz according to the values of the given...
An audio amplifier of good power, and great sensitivity; a simple tuning step and a detecting...
This output stage can directly excite a small speaker. The circuit is from a 1960 Mullard...