Found in American documentation this circuit uses transistors of the time. The circuit can be made with current components. It works as a trigger working with 600 ohm signals.
This circuit is recommended for alarm systems since it has a good output stage. The circuit is...
) Suggested by Philips in a 1968 documentation this circuit has very high 10 ohm on-load voltage...
No information is given about the transformers in this circuit suggested by Motorola in a 1968...