electrical measurements

1. INTRODUCTION TO ELECTRICAL
MEASURING INSTRUMENTS
Prepared by:
Ms. Parneet Kaur Chowdhary
Lecturer, Electrical

2. INTRODUCTION TO
ELECTRICAL MEASUREMENT INSTRUMENTS
VOLTMETER
AMMETER
WATTMETER
ENERGY
METER
OHMMETER
MULTIMETER
CLAMP
METER
MEGGER

3. VOLTMETER
Voltmeter is an instrument, which used for measuring the potential
difference, or voltage, between two points in an electrical or electronic
circuit. It is also known as a voltage meter.
Analog Voltmeter Digital Voltmeter

4. VOLTMETER
• Also we can observe that the Voltmeters can be AC or DC
depending upon the type of voltage to be measured.
• The symbols shown below help us to differentiate between AC and
DC meters
AC Voltmeter DC Voltmeter

5. AMMETER
• An ammeter is a measuring instrument used to measure the current in a
circuit. Electric currents are measured in amperes, hence the name.
• Instruments used to measure smaller currents, in the milliampere or
microampere range, are designated as milliammeters (mA) or
microammeters (μA).
Ammeter Milliammeter Microammeter

6. AMMETER
• Also we can observe that the Ammeters can be AC or DC
depending upon the type of current to be measured.
• The symbols shown below help us to differentiate between AC and
DC meters
AC Ammeter DC Ammeter AC/DC Ammeter

7. WATTMETER
The wattmeter is an instrument for measuring the electric
power in watts of any given circuit.

8. ENERGY METER
• An electricity meter, electric meter, electrical meter, or energy meter is
a device that measures the amount of electric energy consumed by a
residence, a business, or an electrically powered device.
• Electric utilities use electric meters installed at customers' premises for
billing and monitoring purposes.
Electromechanical Energy meter Digital Energy meter

9. OHMMETER
• An ohmmeter is an electrical instrument that measures electrical
resistance.
• Micro-ohmmeters make low resistance measurements.
• Megohmmeters measure large values of resistance.
• The unit of measurement for resistance is ohms.
Ohmmeter Megohmmeter Micro Ohmmeter

10. MULTIMETER
• A Multimeter or a multitester, also known as a VOM (volt-ohm-
milliammeter), is an electronic measuring instrument that combines
several measurement functions in one unit.
• A typical Multimeter can measure voltage, current, and resistance.

11. MULTIMETER

12. CLAMP METER
• In electrical and electronic engineering, a current clamp, also known as current
probe, is an electrical device with jaws which open to allow clamping around an
electrical conductor.
• This allows measurement of the current in a conductor without the need to make
physical contact with it, or to disconnect it for insertion through the probe.
Probes measure voltage.

13. MEGGER
• Megohmmeter or insulation resistance tester is a special type of ohmmeter used to
measure the electrical resistance of insulators.
• Insulation resistance is resistance in ohms of wires, cables, and electrical
equipment, which is used to safeguard the electrical systems like electrical motors
from any accidental damages like electrical shocks or sudden discharges of current
leakages in wires.
Hand-operated Megger Electronic Megger

14. LET’S REVISE
Sr.
No.
Electrical Parameter
Measuring
Instrument
1 Voltage Voltmeter
2 Current Ammeter
3 Power Wattmeter
4 Energy Energy Meter
5 Resistance Ohmmeter
6 Voltage, Current and Resistance Multimeter
7 Voltage, Current and Resistance Clamp Meter
8 Insulation Resistance Megger