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.
This circuit is from a 1967 documentation. It consists of a sensor for memories used at the time....
We found this circuit in the November 1992 issue of Radio Electronics magazine. The circuit has...
Found in EEE documentation, this circuit can have the duration and frequency adjusted separately....