This 300 Hz to 3.4 kHz filter was found in the May 1989 Radio Electronics magazine. The circuit requires a symmetrical power supply.
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...