Question

What is the leastcount of a Microammeter?

Answer 1

Hint: Milliammeters and microammeters are instruments that measure tiny currents in the milliampere or microampere range. The first ammeters were laboratory equipment that operated by using the Earth's magnetic field. Improved instruments, which could be installed in any location and permitted precise measurements in electric power systems, were developed by the late nineteenth century. In a circuit, it is usually symbolised by the letter 'A.'

Complete answer:
An ammeter is a device that measures the current flowing through a circuit. The term comes from the fact that electric currents are measured in amperes (A). The ammeter is generally wired in series with the circuit that will be used to measure the current. The resistance of an ammeter is generally low so that it does not produce a substantial voltage drop in the circuit being monitored. Because every ammeter has a range selector, the least count cannot be generalised. Count the number of tiny divisions on the scale if the range of a particular microammeter is between 0 and 600 mA. The microammeter's least count is \[\dfrac{{600}}{{60}}{\text{ }} = {\text{ }}10{\text{ }}mA\] if there are 60 divisions. The lowest division that an instrument can measure is represented by its least count.
For small fractional amperes, the majority of ammeters are either linked in series with the circuit carrying the current to be measured, or their shunt resistors are also connected in series. The current flows through the metre or (mainly) via its shunt in either instance. Ammeters should not be connected directly across a voltage source since their internal resistance is extremely low, allowing excess current to flow. The additional circuit losses created by the ammeter are referred to as its "weight" on the measured circuit. Ammeters are intended for a minimal voltage drop between their terminals, often less than one volt.

Note: A current transformer in an AC circuit transforms the magnetic field surrounding a wire into a tiny AC current, usually 1 A or 5 A at full rated current, that may be measured by a metre. Similarly, Hall effect magnetic field sensors have been used to create precise AC/DC non-contact ammeters. A portable clamp-on ammeter, which is briefly clamped over a wire to measure current, is a typical instrument for repair of industrial and commercial electrical equipment. A parallel pair of magnetically soft probes is positioned on either side of the cable in certain newer kinds.