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.
With this circuit it is possible to use an oscilloscope as a quick component test, checking its...
This circuit also functions as a phase detector. The components used are not common. We found this...
Using period transistors, this 10 W amplifier was found in Radio Electronics magazine from May...