Short answer, because it is designed for DC, not AC.In AC, the current goes back and forth all the time; the average current is zero. And that's what a galvanometer that is not especially designed for AC would show.
yes it can read both ac and dc voltage and current .AnswerThe whole point of a multimeter is that it can perform the function of an ammeter, a voltmeter, and an ohmmeter!
The ammeter is used in series, because you want to measure the current through a circuit. The voltmeter is used in parallel, because you want to measure the voltage across a circuit. If you were to place the voltmeter in series, no current would flow because of the relatively high impedance of the voltmeter. If you were to place the ammeter in parallel, you would create a short-circuit, due to the relatively low impedance of the ammeter.
dc ammeter has three connecting pins while ac has four
A: It is a regular DC voltmeter but the AC is rectified and the DC component is measured and displayed as AC VOLTS.
voltmeter
A multimeter measures electrical properties such as AC or DC voltage, current, and resistance. Rather than have separate meters, a multimeter combines a voltmeter, an ammeter, and an ohmmeter. The two main kinds of a multimeter are analog and digital. A voltmeter measures the potential difference (voltage) between two points. the voltmeter only measures volts.
I use a Fluke ammeter.
In measuring high AC currents a current transformer with a suitable rating say 100/5 or 1000/5 are used. The secondary current is usually 5 amps when the fulload current of 100 or 1000 as the case may be is flowing in the mains. It is the univerasl practice to use CT's for measurement of AC currents. In DC circuits the transformer method will not work, so to increase the current that you can measure you can allow a known amount of current to bypass the ammeter and recalibrate the ammeter. In other words, put a shunt in parallel with the ammeter.
Measures current, both AC or DC, usually in Amps.
An AC voltmeter is ideal. If you really want to get fancy and analytic about it, you could use data-acquisition equipment to constantly read the AC voltmeter, and store or record the data.
The electrolytic capacitor is most often used in power supply circuits to filter the rectified AC.
No transformers only work with AC.