Vibrating Probe Electrometer for the Measurement of Bioelectric Potentials

Abstract

An instrument is described for measurment of bioelectric, membrane and diffusion potentials without drawing current from the source of potential. A vibrating metallic probe is brought close to the surface to be measured. As long as a potential difference exists between the probe and surface, the induced charge on the former undergoes alteration with the change of capacity due to vibration of the probe. A potential divider introduces an opposing potential between surface and ground, and is varied until the amplified tracing on the cathode-ray oscillograph becomes zero.