This circuit was found in the February 1993 issue of Radio Electronics magazine. Some components depend on the crystal frequency and can be changed.
Under this name, Radioelectronics magazine published in the January 1974 issue a light exposure meter...
This circuit was found in Radio Electronics magazine from September 1965. It uses a thermal...
This power control from Motorola's 1971 SCR Power Control Fudamentals can control full wave loads...