This 555 IC circuit was found in June 1984 Radio Electronics magazine. This circuit detects a change in the signal and can power a relay or other warning system.
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...