In electrical and electronic engineering, a current clamp is a device that measures electrical current in a conductive material. It is made up of a pair of jaws that close around an electrical conductor to measure the flow of electricity through the material. Current clamps can be used to both induce and measure current in conductive materials.
The iron vane is one type of current clamp. The electrical current being measured causes a change in the device’s internal magnetic core in this type of current clamp. An iron vane is moved by the changing magnetic field, which is fixed to a pointer on an analog dial. Both direct current (DC) and alternating current (AC) can be measured with an iron vane clamp meter (AC).
Current clamps are most commonly found in current transformers, and they serve a slightly different purpose than iron vane clamps. A wire coil is wound around a split ring made of iron compounds in these. The conducting material is the primary part of a current transformer, and this winding is the secondary part. The current clamp found in transformers is used to measure and monitor the current in the power grid. This type of current clamp is only useful when measuring AC because transformers only work with AC electricity.
The Hall effect current clamp is another type of current clamp that can measure both AC and DC. The Hall effect is the influence of a magnetic field on the flow of electrons in a conductor, as indicated by the name. These current clamps are extremely sensitive, and they’re frequently used in conjunction with computerized voltmeters. They can be small enough to be carried in one’s hand and run on a 9-volt battery. Hall effect clamps can also handle a wide range of AC frequencies, up to 400 Hz in some cases.
A highly specialized type of current clamp is used in biology to measure voltages generated by the action of a single cell. Electrical activity can be recorded both outside and inside a cell using cellular current clamps. Microelectrodes, which are small enough to measure cellular electricity, are used in devices that measure and record biological voltages. They usually record very low voltages, on the order of 0.0001 volts.