Found in an old English publication, this circuit applies to the 240 V network, but can be changed to lower voltages. Transistors are mostly general-purpose, admitting modern equivalents.
This circuit makes use of a specific 80's component and was found in an American manual of the...
The circuit shown in the figure, generates a positive pulse whose duration depends on C1, from the...
We found this circuit on the internet. The components are current, and the time depends on C1...