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 48 V circuit with a capacity of up to 105 V was found in a 2005 Linear Technology manual. The...
The selected circuit in the Texas Instruments opto-electronics manual works with photoelectric sensors in...
This circuit is from 1964 documentation but can be easily implemented based on current components....