Current Transformers
Current transformers are used to obtain the measure of current in an AC power transducer. Current transformers also retain the ability to transform current to a value suitable for measurement or control. These transformers provide isolation and a step-down current output. Accuracy and cost of current transformers are influenced by the choice of core material chosen.
In a current transformer, the wire to be gauged is placed within the opening of the device and a measure of either alternating voltage or alternating current is produced. The simplest form of a current transformer consists of two coils of wire, electrically insulated from one another and arranged so that a change in the current in one coil (the primary) will produce a change in voltage in the other (the secondary). The transformers are designed to provide a current in its secondary which is accurately proportional to the current flowing in its primary.
There are several types of current transformers including protective, measuring, air-gapped, anti-remanence, wideband and linear current transformers as well as differing styles including split core and clamp-on current transformers. Current transformers are very popular in the electrical power field, as they are able to measure large currents in the presence of high voltages.