Electrical measurements with an electronic microforce balance

Abstract

By using an electronic microforce balance to measure the attractive force the attracted disk electrometer is made a convenient laboratory instrument. An electrometer constructed to measure surface charges on solid dielectrics is described. The dielectric sample partially fills the gap of a parallel plate capacitor and the surface charge is calculated from the force on one plate of the capacitor and its geometry. The instrument described has a sensitivity of 25 nc m⁻². The instrument can also be used to measure static dielectric constants and as an absolute voltmeter.