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Electric Potential Difference And Electric Current
Electric current
Electric potential difference (p. d) is defined as the work done per unit charge in moving charge from one point to another. It is measured in volts.
Electric current is the rate of flow of charge. P. d is measured using a voltmeter while current is measured using an ammeter. The SI units for charge is amperes (A).
Ammeters and voltmeters
Ammeter:
An ammeter is used to measure current that flow in a circuit. It has a small resistance. It is connected in series in the circuit so that the current it will measure should flow through it.
Ammeter is an instrument that is used for measuring current. Ammeters that can detect and measure small current are called milliameters. Galvanometers are ammeters that can detect and measure very small current.
Sensitivity Of Ammeter:
An ammeter is said to be sensitive if it can detect and measure a very small current or detect and measure current no matter how small the current may be.
Ammeters are connected in series in a circuit so that the current the ammeters are to measure will flow through the ammeter themselves. Ammeters are said to be accurate if it can detect and measure the exact amount of current that flows through it or if the current it detect and measure is very close to the value of current that flows through it.
Voltmeter:
A voltmeter is used to measure the voltage or potential difference across a component in a circuit. It has a large resistance. It is connected in parallel across the component whose voltage drop is to be determined. It takes in negligible amount of current.