Electrostatic voltmeter and fieldmeter measurements on GMR recording heads

The purpose of this paper is to provide information on the use of electrostatic fieldmeters and electrostatic voltmeters to make field and voltage measurements on GMR recording heads. Charge is often impractical to measure directly, requiring that the charged object be transfer-red into a Faraday enclosure and then measured using a coulombmeter. When this transfer method cannot be used, charge is often evaluated indirectly by detecting the electrostatic field associated with the charge using an electrostatic fieldmeter or an electrostatic voltmeter. However, electrostatic fieldmeter and electrostatic voltmeter measurements are often difficult to interpret. The goal of this paper is to introduce several types of electrostatic fieldmeters and electrostatic voltmeters, explain the operating principles of each type of instrument, and to describe some of the capabilities and limitations of each ty pe for making measurements on small objects such as GMR recording heads.