This trigger uses two switching transistors that can still be found with some ease. The circuit is from an old documentation and its purpose is to speed up the switching of logic circuits.
This sensor circuit from a 1967 Ferranti documentation uses components from the era. The circuit...
This is the receiver for the previous circuit transmitter. Similarly, no information about the...
Found in a 90s Popular Electronics, this circuit uses two PLL tone recognizers to trigger by touch an...