This 1965 circuit uses a Philips 4068 tube to measure extremely small charges. The circuit has as indicator a micro ammeter and the transistors are of the time.
In the figure we have a security system consisting of a sophisticated alarm found in a 90s edition...
The purpose of this circuit found in an American 1980s documentation is to produce a current pulse to...
The transistor used in this circuit is uncommon today. AC124 or equivalent such as AC188K and...