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.
The voltage gain of this circuit is 1,000. This gain is given by the ratio between the 10 M ohm...
This circuit was found in an old publication about transistors. The circuit can be used to drive...
The circuit presented with low drift is from the Motrorola LinearDatabook of 1990. The circuit...