This circuit is powered by a voltage of 4.5 V, being common in radios of the 60's. The circuit is from Mullard's transistors reference manual.
This circuit includes a battery charging system and an inverter for operating a fluorescent lamp....
This is one of the many versions of cricket that the reader can find on this site. This circuit is...
This circuit emits a sound when a magnetic field, of a magnet, for example, approaches the sensor....