We found this circuit in a 1996 publication. Equivalent components can be tried, especially in the case of the photodiode. The circuit is powered by a 12 V source.
Found in a 1964 Electronic Design, this circuit shows how to modulate a signal with a dynamic low...
This circuit is from an 80's documentation, firing when the input voltage exceeds 5 V. The SCR can...
The transistor used is one of the first power Darlingtons with a collector current of 3 A. The...