Null Indicator

null indicator

[′nəl ‚in·də‚kād·ər]
(engineering)
A galvanometer or other device that indicates when voltage or current is zero; used chiefly to determine when a bridge circuit is in balance. Also known as null detector.

Null Indicator

 

a sensitive instrument for detecting the inequality of physical quantities being compared in the null method. A null indicator may be a galvanometer, electrometer, telephone, or cathode-ray tube. If necessary, the sensitivity of a null indicator can be improved by means of photoelectric, electronic, and other types of amplifiers. Automatic adjustment of the sensitivity of null indicators is widespread; it makes possible the use of maximum sensitivity near zero and sharply reduced sensitivity far from zero. In automatic balancing, a null indicator controls a balancing system.

References in periodicals archive ?
The virtual ground that the opamp provides via feedback through the reference resistance [R.sub.f] is equivalent to the null indicator in a bridge.
The phase equilibrium of the tensions obtained at the switch output (2) and, at the homologous terminals of the tested transformer 5, is compared with a phase discriminator 4 and a null indicator 6.
“With its built-in null indicator and smart setup using two front panel pushbuttons, the SC-100 can be calibrated to work with virtually any standard LVDT in the marketplace.”
* A built-in null indicator and smart setup with 2 front panel pushbuttons.