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Ammeter Voltmeter

The document discusses different electrical measuring devices including ammeters, galvanometers, voltmeters, ohmmeters, and multimeters. Ammeters measure electric current and are connected in series. Galvanometers measure current using a coil in a magnetic field. Voltmeters measure potential difference and are connected in parallel. Ohmmeters measure resistance by creating a current through an internal voltage source. Multimeters can measure voltage, current, resistance, and other electrical properties in a single handheld unit.

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farihakanwal2021
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61 views17 pages

Ammeter Voltmeter

The document discusses different electrical measuring devices including ammeters, galvanometers, voltmeters, ohmmeters, and multimeters. Ammeters measure electric current and are connected in series. Galvanometers measure current using a coil in a magnetic field. Voltmeters measure potential difference and are connected in parallel. Ohmmeters measure resistance by creating a current through an internal voltage source. Multimeters can measure voltage, current, resistance, and other electrical properties in a single handheld unit.

Uploaded by

farihakanwal2021
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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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
Galvanometer

•The galvanometer is the "classic" device to


measure current
•Based on the fact that a wire carrying current
in a magnetic field feels a force
• Review Physics
• The current flows through a coil in a magnetic
field
• The coil experiences a torque proportional to
current
• The movement of the coil is "opposed" by a
spring
• The deflection of the needle is proportional
to current
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
Simple ohmmeter circuit
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
Multimeter

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