This circuit provides a reference voltage of 2.5 V adjusted in the trimpot. The transistor can be the BC558 (in the drawing it came out as NPN). The control is done by a rectangular input signal.
Found in a PE Hobbyst Handbook, this circuit checks if there is voltage in a power outlet by...
This circuit was found in an article in Electronics Now magazine from June 1998. The sensor...
This circuit generates an FM signal of 4.7 or 10.7 MHz for audio signals on analog TV or FM, with...