Definition: The Kelvin bridge or Thompson bridge is used for measuring the unknown resistances having a value less than 1Ω. It is the modified form of the Wheatstone Bridge. What is the need of Kelvin Bridge? Wheatstone bridge use for measuring the resistance from a few ohms to several kilo-ohms. But error occurs in the …
The most significant difference between the thermocouple and the thermistor is that in thermocouple the sensing parameter is the voltage that induces between the two dissimilar metals. Whereas in thermistor the resistance is the temperature sensing parameter. The other differences between the thermistor and the thermocouple are shown below in the comparison chart. The thermocouple …
Definition: Three-Phase Wattmeter is used for measuring the power of the three-phase circuit. In three-phase Wattmeter, the two separate Wattmeter are mounted together in the single unit. Their moving coils are placed on the same spindle. Three-Phase Wattmeter has two elements. The single element is the combination of the pressure coil and the current coil. The …
Definition: The multimeter or volt-ohm-milli-ammeter (VOM) is the type of meter which performs the multiple functions. In other words, in VOM the multiple measuring functions are combined in a single unit. The multimeter is used for measuring voltage, current and resistance. It contains the circuitry switch which makes the meter to operate like a voltmeter, …
Definition: The ratio of torque to the weight of the moving part of an instrument is known as a torque/weight ratio. It indexes the performance of the instrument. The higher value of torque/weight ratio shows that the instrument has good performances. The value of torque/weight ratio of the moving part of the instrument should not be …
Definition: The instrument uses for determining the sequence of the three-phase system is known as the phase sequence indicator. The change in the sequence of the power supply changes the direction of rotation of the machine. Because of which the entire supply system will be affected. For proper connection, it is essential to know the …
Definition: The capacitive voltage transformer step-down the high voltage input signals and provide the low voltage signals which can easily measure through the measuring instrument. The Capacitive voltage transformer (CVT) is also called capacitive potential transformer The capacitive potential divider, inductive element and the auxiliary transformer are the three main parts of the capacitive potential …
Definition: The Weston frequency meter is a moving iron instrument used for measuring the unknown frequency of a signal. The frequency meter consists one inductive and one resistive coil. When the frequency of the signal varies from standard frequency, the current distribution across the coils becomes changes. Working Principle of Weston Frequency Meter The Weston …
The potential or voltage transformer is a step-down transformer used for transformation of voltage from a high value to fractional value. The measuring instrument like ammeter, voltmeter, wattmeter, etc. designs for low voltages. If the measuring apparatus connects to the high voltage lines for measurement, the devices may get burned or damage. Thus, the potential …
Definition: The thermocouple is a temperature measuring device. It uses for measuring the temperature at one particular point. In other words, it is a type of sensor used for measuring the temperature in the form of an electric current or the EMF. The thermocouple consists two wires of different metals which are welded together at …
