What are electrometer applications?

electromter

What are electrometer applications? What is an "electrometer"?

For what purposes these are used?

Can anyone elaborate a little?

Re: Electromter applications

An electrometer is an electrical instrument for measuring electric charge or electrical potential difference. There are many different types, ranging from historical hand-made instruments to high-precision electronic devices. Modern electrometers based on vacuum tube or solid state technology can be used to measure extremely small currents down to 1 femtoampere.

In modern parlance, an electrometer is a highly sensitive electronic voltmeter whose input impedance is so high that the current flowing into it can be considered, for practical purposes, to be zero. They are of use in nuclear physics as they are able to amplify the tiny 'photo' currents created by radiation. The most common use for modern electrometers is probably the measurement of radiation with ionization chambers

They can be of several types-:
a)Vibrating reed electrometers
b)Valve electrometers
c)Solid-state electrometers