Electrical and electronics measurements miscellaneous Easy Questions and Answers

Electrical and electronics measurements miscellaneous

Equal resistances of 100Ω each are connected in each arm of a Wheatstone bridge which is supplied by a 2 V battery source. The galvanometer of negligible resistance connected to the bridge can sense as low current as 1μs. The smallest value of resistance that can be measured is _________

A unknown resistance is measured by substitution method. First a standard known resistance of 100Ω is connected in series with a circuit having a rheost at and a galvanometer. The battery voltage is 10 V and the setting of the rheostat is 500 Ω and the galvanometer shows a deflection of 60°. After this test, the battery voltage goes down to 9 V and when the unknown resistance is substituted for the known resistance, the galvanometer again shows a deflection of 60° with the same setting of the rheostat. The value of unknown resistance is _________

In the bridge given in the figure, the reading of the high impedance voltmeter is __________V

The meter constant of a single-phase 240 V induction watthour meter is 400 r evolutions per kWh. The speed of the meter disc for a current of 10 amperes of 0.8 p.f. lagging will be ____________ rpm

A digital voltmeter uses a 10 MHz clock and has a voltage controlled generator which provides a width of 10μsec per volt of unit signal. 10 volts of input signal would correspond to a pulse count of ___________

V_ab = 20 ×	1	+ 10 ×	1	= 3.33V
	3		3

V_ab = 20 ×	1	+ 10 ×	1	= 3.33V
	3		3

=	400 × 240 × 10 × 0.8	×	1	rph
	100		3600

=	400 × 240 × 10 × 0.8	×	1	rph
	100		3600