This circuit generates signals in four frequency bands with the threshold values indicated in the diagram. The circuit was found in the March 1996 issue of Electronics Now magazine.
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...