Null Type Measuring Instruments

The null type instruments are also known as zero type electrical instruments. When the pointer on measuring instruments maintain the stationary position then it is conisdered as Null value and hence they are called null type instruments. They are producing opposite effect than deflecting type instruments. Due to opposing effect the pointer position is stationary. Thus for the operation of null type instruments following steps are required:

1. In order to calculate the value of unknown quantity the value of opposite effect must be known.
2. The balance and unbalance condition on the detector must show accurately. The detector should also have the means for restoring force.
   
   
   Look at the camparison of deflection and null type of electrical measuring instruments:

1. Null type of instruments are more accurate than deflection type of instruments. It is because, in the null deflecting instruments the opposing effect is calibrated with the high degree of accuracy while the calibration of the deflection type instruments depends on the value of instrument constant hence usually not having high degree of accuracy.
2. Null point type of instruments are more sensitive than the Deflection type of instruments.
3. Deflection type instruments are more suitable under dynamic conditions than null type of instruments as the intrinsic responses of the null type instruments are slower than deflection type instruments.
   

These measuring instruments are available at electrical equipment suppliers or at any electrical dealers which deals in electrical equipment. You can get any type of instruments from digital clamp meter to digital multimeter to infrared thermometer for troubleshooting of voltage related issues.