Analog measuring device

1. ANALOG MEASURING DEVICES

2. CONTENT
 typing of measuring devices
 Analog measuring devices
1- galvanometer
2- ammeter
3-voltmeter
4-ohmmeter
5-Avometer

3. 1- MEASURING DEVICES
measuring devices
• he digital display shows
the value directly
measuring devices
• consists of a scale through
which the deflection needle
indicates the value to be
measured
First, the measuring devices are divided into two types, analog and digital. The digital
devices rely on digital electronics. It is a device that has a screen on which the
numbers simply appear. As for the analog measuring devices, it depends on the
presence of a pointer and a coil that rotates, and through it results in coupling torque
and power. When the coupling torque is equal to the night torque, the pointer stops
at A certain number, or when measuring the correct, descending devices are less
accurate than digital ones, and they measure direct current only and do not measure
alternating current. Examples of analog devices are the galvanometer with a moving
coil, the ammeter, the ohmmeter, the voltmeter, and the ohmmeter.

4. THE MOST TYPES OF ANALOG MEASURING
DEVICES :
1- Moving – coil type :
They are devices with permanent
magnets that move inside a
current- carrying coil.
The method of operating the
device depends on the movement
of the coil through the mutual
influence between the field arising
from the passage of current in the
moving coil and the field of the
permanent magnet.

5. 2- Moving iron core measuring
devices:
They are devices with a fixed coil
that carries the current, and inside it
is a small piece of wrought iron
mounted on the rotating shaft of the
device.
This iron is magnetized momentarily
as the current passes through the
coil.

6. 3- Moving magnet
measuring devices:
They are devices that
contain two strips of iron
placed in a strong magnetic
field, and the iron strip
acquires the magnetic
property, and a magnetic
repulsion force is generated
on each strip.

7. ANALOG MEASURING DEVICES
1- GALVANOMETER
Galvanometer is an electromechanic
instrument for detecting and indicating
an electric current it sensitive
electromagnetic device which can
measure currents even of the Order of a
few microamperes galvanometer work
as a actuator by producing reflections in
response to electric current flowing the a
coil in a constant magnetic field
Uses
1- It indicates the presence of
weak currents
2- It measures weak currents
3- The source of the electric
current
4- The direction of the electric

8. DEVICE CONFIGURATION
1- CONCAVE ELECTRODES TO MAKE THE FLOW LINES IN THE
FORM OF RADII
2- A THIN COPPER WIRE WRAPPED IN A RECTANGULAR SHAPE
ON AN ALUMINUM FRAME
3- A STAND MADE OF AGATE THAT CAN BE SUPPORTED ON
IT BECAUSE IT IS FRICTIONLESS AND CORROSION-FREE AND
HELPS IN PROPER SUPPORT
4- SPRING COILS, WHICH ARE LINKS FOR THE CURRENT THAT
ENTERS FROM ONE OF THEM AND EXITS FROM THE OTHER.
IT IS AFFECTED BY A TORQUE CALLED THE TORQUE OF THE
COIL. WHEN THE TORQUE OF THE COIL IS EQUAL TO THE
TORQUE OF THE PAIRS, THE POINTER IS FIXED AT THE
CORRECT READING, AND THEY ALSO WORK TO RETURN THE
POINTER TO THE ZERO POSITION WHEN THE CURRENT IS CUT
OFF.
5- ITS CYLINDER IS MADE OF WROUGHT IRON, BECAUSE THE
COEFFICIENT OF PERMEABILITY OF WROUGHT IRON IS HIGH,
SO IT WORKS TO ORGANIZE AND FOCUS THE FLOW LINES IN
THE SPACE IN WHICH THE COIL ROTATES.
6- A LIGHT INDICATOR MADE OF ALUMINUM THAT ROTATES
ON A REGULAR ZERO SCALE IN THE MIDDLE TO INDICATE

9. ......
DISADVANTAGES OF THE
GALVANOMETER
• Changing the temperature will cause a
change within the torque recovery.
• It cannot be used to measure AC
quantities.
• It can only be used to measure direct
currents.
• It develops errors due to factors such as
tool aging, permanent magnets, and
spring damage due to mechanical stress
CHARACTERISTICS OF THE
GALVANOMETER
• It will not be affected by strong or large magnetic
field.
• It is an accurate and reliable device.
• standardized metrics.
• The torque-to-weight ratio is high.
• It has high sensitivity.
• Stray magnetic fields are not easily affected.

10. ANALOG AVOMETER
• Analog Avometer:
• It is a multi- measurement device that
measure both current, voltage and
resistance. There are many forms of it in
the commerical market, and it is called by
this name derived from the following
letters:
• Letter A to measure current Ampere
(Ammeter)
• Letter V to measure voltage in volts
(Voltmeter)
• Letter O to measure resistance in ohm
(Ohmmeter) l

11. •Areas of measurement in which the Avometer can
be used :
1- DC and AC voltage measurement.
2- Direct and alternating current measurement.
3-Measurement of Different types of Resistance.
•Some types of devices can measure a voltage of
up to 50KV, a current of up to 15A, a resistance
of up to 30 MΩ , and the device is provided from
errors in the measurement. It is also provided
from the inside with a number of current dividers

12. HOW TO MEASURE VOLTAGE WITH AN
AVOMETER :
• 1- Adjust the device to the highest voltage value in it, to avoid
any damage to the device.
• 2- Connecting the Avometer in parallel with the circuit, whether
this current is alternating or continuous.
• 3- Connect the device in series with the electrical circuit.

13. • The most important
features of the Analog
Avometer
•1- Low cost
•2- Responsive
•3- No need for
batteries
•1- Primitive device
•2- Perishable
•3- Exposure to
misreading
• The most famous
defects of the Analog
Avometer
The most famous
defects of the Analog
Avometer
The most important
features of the Analog
Avometer

14. AMMETER
An ammeter (abbreviation of Ampere
meter) is an instrument used to
measure the current in a circuit.
Electric currents are measured in
amperes (A), hence the name. For
direct measurement, the ammeter is
connected in series with the circuit in
which the current is to be measured.
An ammeter usually has low
resistance so that it does not cause a
significant voltage drop in the circuit
being measured

15. HOW TO MEASURE WITH AN AMMETER
• It is measured in the unit of the Ampere, called “Amp,” (A). The most
common way to measure current in a circuit is to break the circuit
open and insert an ammeter in series (in-line) with the circuit so that
all electrons flowing through the circuit must also go through the
meter.
INSTALLATION
1) moving coil galvanometer.
2) small resistance called "Shunt
resistance" Rs connected in parallel to the
resistance of the galvanometer coil.

16. 3- VOLTMETER
● The definition of a voltmeter is a device different from
the device that measures the electric current, which is the
ammeter, which relies on measuring the potential
difference mainly, and in the process of measuring it is
based on the internationally recognized unit for
measuring the intensity of electricity, which is the ampere
as the official unit of measurement of the intensity of the
current, and as the unit of measurement of the current
electric current in the international system, while the
second is based on the measurement of the electric
current, which helps us to know how the intensity of the
electric current is calculated, and the work of the
voltmeter is based on the torque, as it is created through
the current that works through the measurement and the
voltage, and after the occurrence of the torque Indicator
deviation occurs.

17. in parallel according to the laws of electric current intensity,there are multiple systems in
connection within devices that help measure electric currents, and one of these methods is
the parallel method, which requires connecting a voltmeter, as this method ensures that the
internal resistance is maintained to be high in a manner Continuous, in addition to that, the
method that is based on connecting to the parallel system when it is connected in series,
this reduces the flowing current, and connecting the voltmeter to the parallel system works
to cause a decrease in the voltage level, as it decreases as a result of the union of the high
resistance of the device With the connected element, however, these steps in the
connection process do not cause any obstructions or difficulties in the voltmeter, and
therefore this device is an accurate measurement, without there being any wrong readings.
The importance of connecting a voltmeter

18. TYPES OF VOLTMETERS
1. is one of the types of
voltmeters that is used to measure voltage,
as the mechanism of this type of voltmeter
measures each AC circuit and the DC
circuit, and in this type of device, the
matching process and measurement are the
same in both types of alternating current
and direct current.

19. 2. An analog voltmeter or as
it is called an analog voltmeter is used to
measure AC voltage, as this device displays the
reading, through the indicator, which is a fixed
indicator based on the calibration scale, as the
deviation of the indicator in this device
depends on the torque, as it should be noted
That the size of the torque, as well as the
measurement effort, have a basic and direct
relationship between them, where the size of
the developed torque is directly proportional to
the measurement effort, so the greater the
torque, the greater the measurement effort,
and the less the torque, the less the

20. 3. A digital voltmeter is
known as a voltmeter device that displays the
reading, in digital form, as this device
determines the pointer accurately, and then
gives a very accurate reading, and the tool that
measures direct current in this device is
known as the “continuous voltmeter”, An AC
potentiometer is used in an AC circuit to
measure voltage.