This TTL delay circuit has long delay times which can be determined by R1 and C1. The base is in common TTL and Maxim's MAX907.
Found in a 90s Popular Electronics, this circuit triggers a load from the audio signal applied to...
This old receiver (1967) uses germanium transistors from the time and coupling transformers,...
I found this circuit in a Popular Electronics from 1992. The circuit can be easily implemented with BC549...