Electrical measurements are those that measure the voltage, current, and power and resistance in an electric circuit. Also included are those that measure electrical characteristics of the circuit itself and the materials or components comprising it. In addition, electrical measurements are measurements made of the electromagnetic field surrounding a conductor carrying an electric current. All types of electrical measurements involve methods, devices, and calculations specific to the measurements being made.
The most commonly-measured quantities in an electrical circuit are usually determined with a meter. An ammeter measures current in amperes, a voltmeter measures voltage in volts, and an ohmmeter measures resistance in ohms. The electrical power of a circuit in watts, which is the product of its voltage and current, can be calculated once those two quantities have been determined, or, if the resistance and one of the quantities is known, by applying Ohm’s Law. The functions of ammeter, voltmeter, and ohmmeter are combined in a device known as a multimeter. It has a switch on the front that allows the user to select the function of the meter and the sensitivity of measurement.
