Using an LDR, this Philips circuit directly activates a relay when light strikes the sensor. The relay is 45 V with 20k coil resistance. The 220 nF capacitor must be polyester for 400 V.
This speed control for motors up to 500 mA was obtained in an old European documentation, but it...
This circuit cuts a rectangular signal, and a trapezoidal signal is obtained. The circuit is from...
This low frequency sinusoidal oscillator was obtained in documentation from the 1970s. Operational...