This circuit without sensors in series triggering an SCR was found in volume 5 of the 1995 Encyclopedia of Electronic Circuits. The circuit can have the number of sensors changed.
Found in a Maxim documentation from the 1990s, this current-sensing amplifier uses components from the...
We found this circuit in a 1982 documentation. An intercom to be good must be sensitive and have...
This circuit is from a 1980s documentation, but the configuration can be applied to most modern...