Current-to-voltage amplifier with a high voltage isolated input
Abstract
The measurement of very low currents collected on electrodes held at high voltages is a commonly encountered experimental problem, since a commercial electrometer's input can usually be floated only at a few tens of volts. We have run into this problem when attempting to measure the gain of the first dynode of an electron multiplier of the type used on cesium-beam atomic clocks. In order to solve it, we have designed, built, and tested a current-to-voltage (transresistance) amplifier whose input can be floated up to ±2000 V, while providing a ground-referenced low-impedance output capable of driving a voltmeter or chart recorder. This very flexible instrument can measure currents in the 10-12 -10-7-A range, has a 1-Hz bandwidth, and it can be built at a cost of a few hundred dollars.
- Publication:
-
Review of Scientific Instruments
- Pub Date:
- June 1989
- DOI:
- 10.1063/1.1140286
- Bibcode:
- 1989RScI...60.1197J
- Keywords:
-
- Current Amplifiers;
- Electrical Measurement;
- Electrical Resistance;
- Field Effect Transistors;
- Operational Amplifiers;
- Voltage Amplifiers;
- Calibrating;
- Capacitors;
- Resistors;
- Instrumentation and Photography