Found in the July 1994 Electronics Now magazine, this circuit drives a relay up to 12 V depending on the power supply. The transistor can be general purpose.
This circuit is from a publication of the 70s, but it can be easily assembled with the BC548. The...
This very low frequency amplifier has a gain of 1,000 and was found in a 1967 documentation. The circuit is...
This transmitter was found in a 1993 documentation, but it can be assembled with operators like...