This timer was found in Japanese documentation from the 1960s. The transistor can be replaced by an equivalent and the relay must be of the sensitive type with voltage according to the power supply.
This circuit is from 80s documentation, using still common CMOS components. The display is 7...
This circuit was obtained in an English magazine from 1979, but it can be easily assembled with...
Found in Electronics Now, this circuit generates signals for testing like a signal injector. The...