This circuit was found in the April 1998 issue of Electronics Now magazine. The circuit uses common operational amplifiers and uses a dual power supply.
This timebase was found in a European 1980s documentation. The circuit uses well-known components...
This amplifier stage with 1 power transistor was found in the Radio Electronics magazine of...
The basic idea of this 1989 circuit is to trigger a relay for a while when a call signal occurs on...