This circuit was found in an article about the 555 in the November 1992 Radio Electronics magazine. The circuit uses a 12 V relay and has two timing ranges.
This amplifier with differential input uses two old op amps but can be implemented with modern op amps....
This power supply was found in the December 1970 issue of Radio Electronics magazine. The...
This circuit is a wireless temperature transmitter for RF signals in the range of 0.2 to 2 MHz...