This simple circuit is a continuity test that, in addition to testing resistors, can also test other components. Power is provided by batteries and the LED can be of any color.
This circuit, published in the 1980s, can be applied to operational amplifiers of almost any type....
This touch sensor, found in an American documentation on transistors, has gained 8 million times...
This is one of the many versions of cricket that the reader can find on this site. This circuit is...