This circuit can detect static charges or extremely low voltages. The circuit was found in ancient American documentation and makes use of a JFET. A BF245 which is a more modern transistor can be used.
This circuit produces the ticking of a clock on a common piezoelectric transducer. The circuit has an...
The basis of this circuit is a double T in the feedback, which has the components calculated to...
This configuration was found in the Texas Instruments optoelectronics manual. PNP transistors...