Found in a 90s documentation, this circuit makes use of D1, a switching diode that is uncommon today. D3 is an LED. The circuit monitors 12 V batteries.
This 80's circuitry decodes stereo signals used in analog TV at the time. The circuit can be used...
This is the normal circuit of a relaxation oscillator using an unijunction transistor such as the...
This circuit is from a 1967 publication and applies to incandescent lamps up to 600 W. Triacs must be...