ABSTRACT
Charge measurement is widely used in electronics, physics, radiology, and light and particle detection, as well as in technologies involving charged particles or droplets (e.g., toners used in copiers). Measuring charge is also the method of choice for determining the average value for small and/or noisy electric currents by utilizing time integration. The two standard classes of charge-measurement devices are the electrostatic voltmeters and the charge amplifiers. Trace chemicals in the circuitry can give rise to electrochemical currents. It is therefore important to thoroughly clean and dry chemicals of all sensitive circuitry. Optical methods of charge measurement are also used for particles whose physical structure depends on their charge. An example is the degree of dissociation of the end groups of polystyrene particles in colloidal solutions. A widely used application of charge measurement is as an integral element of radiation dosimetry. Radiation is passed through ionization chambers, where the generated ions are collected and the charge measured with electrometers.
