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AC and DC meters. Ammeter . Ammeter is an electrical measuring device, which is used to measure electric current through the circuit. CONNECTION OF AMMETER IN CIRCUIT An ammeter is always connected in series to a circuit. SYMBOL . Ammeter . Ammeter is a low resistance galvanometer
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Ammeter Ammeter is an electrical measuring device, which is used to measure electric current through the circuit. CONNECTION OF AMMETER IN CIRCUIT An ammeter is always connected in series to a circuit. SYMBOL
Ammeter • Ammeter is a low resistance galvanometer • It is used to measure the current in a circuit in amperes • Galvanometer can be converted into an ammeter by using a low resistance wire in parallel with the galvanometer • the resistance of the wire depends upon the range of the ammeter • As shunt resistance is small the combined resistance of the galvanometer & the shunt is very low hence the ammeter has much lower resistance than galvanometer • An ideal ammeter has zero resistance
Voltmeter Voltmeter is an electrical measuring device, which is used to measure potential difference between two points in a circuit. CONNECTION OF VOLTMETER IN CIRCUIT Voltmeter is always connected in parallel to a circuit. SYMBOL
Voltmeter • Volt meter is a high resistance galvanometer • It is used to measure the potential difference between two points of a circuit in volts • A galvanometer can be converted into a volt meter by using a high resistance in series with the galvanometer • The value of resistance depends upon the range of the volt meter • For voltmeter a high resistance, R is connected in series with the galvanometer therefore resistance of voltmeter is very large as compared to that of galvanometer • The resistance of an ideal voltmeter is infinity
Ohmmeter • The purpose of an ohmmeter, is to measure the resistance placed between its leads. • This resistance reading is indicated through a mechanical meter movement which operates on electric current. • The ohmmeter must then have an internal source of voltage to create the necessary current to operate the movement • Also have appropriate ranging resistors to allow just the right amount of current through the movement at any given resistance
Multimeter • A multimeter is a device used to measure electrical current, voltage, and resistance.A multimeter combines several electrical meters into one handheld unit. • Basic multimeter models can measure voltage, current and resistance. • Advanced models can also measure temperature, inductance, capacitance, duty cycle and frequency. • They can also test diodes and transistors. • Some even work as an oscilloscope. • The two main types of multimeter are digital and analogue