We found this circuit in a 1967 General Electric SCR manual. The time is set to R1 and depends on C1 which must be a low-leak capacitor.
This circuit, which is part of a percussion instrument, was found in the September 1979 issue of...
The circuit shown in the figure, generates a positive pulse whose duration depends on C1, from the...
Found in the 1989 Radio Electronics Experimenter special edition, this circuit was designed for...