May 14, 2009 Leave a comment
Digital voltmeter(DVM) IS AN indicating device. The main use of DVM is to measure voltage between two points. It displays d.c. Or a.c voltage as discrete numerals. It is an useful laboratory instrument for several applications. It is also an useful building block of digital instrumentation systems. The utility of DVM can be easily extended for multiple functions, such as in a Digital multimeter by the addition of simple auxiliary hardware. The DVM is often used in data processing system.
An ideal voltmeter has an infinitely high input resistance so that it doesn’t draw any current from the circuit. Consider a never which has a low input resistance of 1000 ohm. It can not give an accurate value of the voltage across a resistance of the same magnitude because the meter shunts the resistance. Therefore, it is important to measure the loading effect of a voltmeter in terms of ohms per volt.