Our life is incomplete without electricity. Whatever we do, be it watching television, working on laptop, using tube lights for light, using microwaves, charging batteries for our cars or vehicles, all of these need electricity. At the end of the month, we get an electricity bill which we need to pay. We need to pay for the amount of electricity we have used. How do we measure the amount of electricity used by us? We use ammeter for this purpose.
Ammeter is derived from the combination of words Ampere plus Meter. Ampere is the SI unit of current. Ammeter is used to measure the amount of electric current used by an electrical appliance. For measurement of current in smaller range, we use smaller version of ammeter called milliammeters and microammeters. They measure current in the range of milliampere or microampere.
DIFFERENCE BETWEEN CURRENT AND VOLTAGE –
Voltage is the electrical potential difference per unit charge, or can be defined as the energy contained within an electrical circuit. Current is the rate at which electric charges passes through the circuit.
USAGE OF AMMETER –
It is of utmost importance that the electrical connections in the circuit are correct, else they can cause short circuits and fires in many cases. The rule of current says –
V = I / R (V = voltage, I = current, R = resistance)
The ammeter offers low electrical resistance to the circuit. Lower the resistance, higher the current. If we connect the ammeter in parallel to the circuit, this imposes two problems. Now since, there are multiple paths through which the current can flow, large amount of current would flow in the branch of the ammeter. In this way the circuit would not get the required current and ammeter would not get the correct reading. The second problem is that it might cause short-circuit of the ammeter or the electrical circuit. And thus the Ammeter’s wire tends to burn out.
If the ammeter is connected in series to the circuit, there are no alternate paths and the entire current goes through the circuit. In this case, ammeter measures the correct value of current in the circuit.
Voltmeter on the other hand is always connected in parallel, because it offers high resistance. Higher the resistance, lower the current. Hence it will receive a lower current and the circuit would get sufficient amount of current.