This circuit was found in an article about the 555 in the November 1992 Radio Electronics magazine. The circuit uses a 12 V relay and has two timing ranges.
This is the old name given to flip-flops or biestable multivibrators. In fact, this is a 1967...
This 5.1 MHz oscillator was found in a 1980s American documentation. The used operational...
We found this circuit in an old English documentation from the 70s. The transistor can be a modern...