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 was taken from old American documentation. The transistors used make it possible to...
This oscillator uses a general-purpose transistor that can have BC548, BF494 or 2N2222 equivalents and...
This circuit of a 73 American magazine from the 1990s can generate multiple frequency signals from the...