This circuit is from a documentation on the MC1539 from Motorola and may, however, be implemented with equivalent operations. The transistor also supports equivalent.
This simple electroscope with bipolar transistors is not the most sensitive, but can detect static...
This circuit is suggested by Texas Instruments in his Optoelectronics Sourcebook. Any photo...
The frequency generated by this circuit depends on the crystal used. Frequencies up to a few tens...