High voltage probe

High voltage probe testing

The high voltage probe is an essential part of precision high voltage measurement. The high voltage probe accurately attenuates the high voltage to a low level which can be safely handled and easily measured with a meter. The design of the high voltage probe, needs to take into account proper creepage and clearance distances, as well as, the dielectric properties of the materials used. The high voltage probe attenuator usually consists of one or more high impedance resistors. To optimize performance and accuracy, the attenuator resistors should have both a low temperature coefficient of resistance and a low voltage coefficient.

The range of high voltage probes vary widely. 10KV, 20KV, 35KV, 70 KV and 100KV are among the most commonly requested values. If the high voltage probe is intended to be used in an AC application, then the attenuator design should minimize inductance, in order to provide good AC performance characteristics. High voltage probes resistors typically utilize a serpentine pattern in order to minimize inductance. Low inductance aids in optimizing AC bandwidth.

Not all high voltage probes are used for measurement applications. Some high voltage probes, such as those used with hipot testers, are strictly insulated, cylindrical housings which act as a safe conduit to allow the user to apply high voltage to a specific test point via the exposed conductive tip.