This circuit was found in an Electronic Design from the 90s. The shapes of the signals obtained as result of the inputs are shown next to the diagram.
This simple circuit, which requires a low current (50mA) relay for 5 to 12V power supplies, was...
We found this circuit in a publication from the 1970s, but it can still be assembled today by...
Found in a Motorola documentation from the 70s, this circuit makes use of transistors of the time....