JMJ
MARIST BROTHERS
NOTRE DAME OF DADIANGAS UNIVERSITY
MARIST AVENUE, GENERAL SANTOS CITY

MULTITESTER
Instrumentation and Control
CpE 511

NAME: KURT RUSSEL C. CHUASeptember 01, 2012
CYNTHIA C. GONZAGADate of Submission

INSTRUCTOR: ENGR. JAY S. VILLAN, MEP-EE

Introduction
A multitester or multimeter is a device which can be used to gather data about electrical circuits. A basic multitester can measure resistance, voltage, and continuity; while more advanced versions may be able to provide additional data. This tool can be very useful to have around the house, and anyone who plans on doing electrical repairs should most definitely use a multitester for safety reasons. Multitesters can be used with the current off or on in most cases, although using the device with the current on can sometimes result in damage to the device.

Theory
Ammeters are employed for measuring current in a circuit and connected in series with the circuit. As ammeter is connected in series, the voltage drop across ammeter terminals should be as low as possible. This requires that the resistance of the ammeter should be as low as possible. The current coil of ammeter has low current carrying capacity whereas the current to be measured may be quite high. For this reason a low resistance is connected in parallel to the current coil. Voltmeters are employed to measure the potential difference across any two points of the circuit these are connected in the parallel to the circuit. The resistance of voltmeter is kept very high by connecting a high resistance in series of the voltmeter with the current coil of the instrument. The actual voltage drop across the current coil of the voltmeter is only a fraction of the total voltage applied across the voltmeter which is to be measured. An ohmmeter is a measuring instrument used to measure the resistance placed between its leads. The resistance reading is indicated through a mechanical meter movement...

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c h a p t e r
2
Resistance
No pain, no palm; no thorns, no throne; no gall, no glory; no cross,
no crown.
—William Penn
Historical Proﬁles
Georg Simon Ohm (1787–1854), a German physicist, in 1826
experimentally determined the most basic law relating voltage and current for a resistor. Ohm’s work was initially denied by critics.
Born of humble beginnings in Erlangen, Bavaria, Ohm threw himself intoelectrical research. Ohm’s major interest was current electricity, which had recently been advanced by Alessandro Volta’s invention
of the battery. Using the results of his experiments, Ohm was able to
deﬁne the fundamental relationship among voltage, current, and resistance. This resulted in his famous law—Ohm’s law—which will be covered in this chapter. He was awarded the Copley Medal in 1841 by the
Royal Society of London. He was also given the Professor of Physics
chair in 1849 by the University of Munich. To honor him, the unit of
resistance is named the ohm.
Ernst Werner von Siemens (1816–1892) was a German electrical
engineer and industrialist who played an important role in the development of the telegraph.
Siemens was born at Lenthe in Hanover, Germany, the oldest of
four brothers—all of whom were distinguished engineers and industrialists. After attending grammar school at Lübeck, Siemens joined the
Prussian...

...electric fire element. This wire has much more resistance. Energy has to be spent to force electrons through it. And heat comes off as a result.
All conductors have some resistance but:
 Long wires have more resistance than the short wires.
 Thin wires have more resistance than thick wires.
 Nichrome wire has more resistance than copper wire of the same size.
Resistance is calculated using this equation:
VOLTAGE
RESISTANCE =
CURRENT
The unit of resistance is the ohm
Here is an example:
If there is a voltage of 12 volts across this nichrome, then a current of 4 amperes flows through.
So: 12
Resistance = ohms
4
= 3 ohms
If there is a voltage of 12 volts across this piece of nichrome, then a current of 2 amperes flows through.
So: 12
Resistance = ohms
2
= 6 ohms
The higher the resistance, less current flows for each volt across the wire.
Like electric fires, kettles and hairdryers have heating elements made from coils of thin nichrome wire. The wire gives off heat when a current passes through. But that isn't their job. In some circuits , they are used to reduce the current. In radio or TV circuits they keep currents and voltages at the levels needed to make other parts work properly.
In a variable resistors...

...Resistance coursework
Aim: My aim is to find out which factors affect the resistance of wire and how they affect them.
Ohm's Law:
Ohm's law is also relevant to know of Ohm's Law, which states that the current through a metallic conductor (e.g. wire) at a constant temperature is proportional to the potential difference (voltage). Therefore V ¸ I is constant. This means that the resistance of a metallic conductor is constant providing that the temperature also remains constant. Furthermore, the resistance of a metal increases as its temperature increases. This is because at higher temperatures, the particles of the conductor are moving around more quickly, thus increasing the likelihood of collisions with the free electrons.
Resistance is the ratio of Voltage : Current and we calculate it by using the equation R=V/I.
Variables:
 Material of wire: In my experiment I will be using wire, because it has a high resistance. This could be either it has a closer ions or more ions than other metals. For example Copper has a low resistance due to the arrangement of its ions.
 Temperature: A rise in temperature causes ions inside the metal to vibrate more causing electrons to collide into them this builds resistance; therefore the electrons find it harder to get through the wire. The greater the temperature the greater the...

...Measuring Resistance Experiment Evaluation
M U S (12037486)
Table of Contents
Title Page 1
Introduction 3
Research Questions 4
Questions 4
Answers 4
Experiment 6
Introduction
This experiment is carried out to show how the
Research Questions
Questions
1) Provide the units used to measure the following quantities, electric current, inductance, frequency, power and energy (work).
2) What is the difference between AC and DC voltages? Give examples.
3) Provided a household has:
* 10 light bulbs of 60 watts each (used 6h/day on average)
* TV using 100 watts (used 4h/day on average)
* A washing machine using 1000 watts (used for 3 /h once every 3 days)
Calculate the total average energy consumption of this household in a quarter (90 days) in joules than in Kilowatt hours (kWh).
4) If the energy consumption is charged at 20p/kWh, what is the cost of the electricity bill for that quarter?
Answers
1) The following quantities are measured in the following units;
- Electric Current is measured in Ampere, A.
- Inductance is measured in Henry, H.
- Frequency is measured in Hertz, Hz.
- Power is measured in Watts, W.
- Energy (work) is measured in Joules, J.
2) AC
3) Power = Energy / Time, therefore Energy = Power x Time.
i) 10 bulbs x 60 Watts = 600 Watts, 600 Watts x 6 Hours = 3600 Wh = 3.6 kWh per day.
ii) 100 Watts x 4 Hours = 400 Watts = 0.4 kWh per day.
iii)...

...students were introduced to the field of electrical engineering. The objectives of the lab were to determine the resistance of a resistor using various methods and to also verify Ohm’s Law. In the lab, the students were instructed to calculate the resistance by using color codes, measuring the resistance using a Digital Multi Meter, calculate the average resistance from 10 voltage and current measurements, and find the graphical resistance using a trend line. The results show that the average resistance calculated from 10 voltage and current readings and the graphical resistance were closest to the measured resistance, while the color coding resistance was furthest off.
Introduction:
Georg Simon Ohm established that current (I) in a wire is proportional to the voltage (V) applied to its ends. How much current flows in the wire depends on the voltage but also on the resistance (R) of the wire. A higher resistance yields a lower current for a given voltage. (I= V/R) This is known as Ohm’s Law, where V is measured in volts, I is measured in amperes, and R is measured in ohms. Electrical engineers have to build devices that control the flow of electrons. Changing the shape or choosing different materials with different resistance are ways that they do this. A resistor is a passive...

...Data Analysis
The investigation I did was to find the resistance of a piece if wire. The piece of wire is my dependent variable throughout the investigation. I changed the length of the wire in order to measure the resistance of each length.
Plan
In this investigation, a simple circuit will be set up to read the voltage and current when the length of the wire changes. The length will range from 10cm-80cm with intervals of 10cm. The length of the wire will be changed by moving the crocodile clip across the wire and checking the measurements with a ruler.
The circuit should be set up as in the circuit diagram (as attached). The voltmeter should be set up parallel to the ammeter. The readings from the ammeter and voltmeter will be used to work out the resistance. This can be done using the formula: R = V/I (V is the potential difference in volts, I is the current in amperes (amps), R is the resistance in ohms, Ω)
Safety
In order to perform a safe experiment, a low voltage of 4v was chosen so that it won’t over heat and to avoid electrocution. The power pack must be turn off between readings/ when moving the wire. If the wire gets hot or if there’s a smell, the plug should be turned off immediately.
Fair test
To ensure that the investigation is carried out in fair way, the wire must be measured as accurately as possible and the same circuit and power supply must be used throughout as different power supplies...

...An experiment to investigate the factors which affect Resistance in a wire
What is resistance?
A potential difference (V) applied across a wire of length (l), there is in the conductor, an electric field (E). In this electric field the free electrons are not however under continuous acceleration (Ee/m). This is because they repeatedly collide with the moderately massive vibrating atoms losing their kinetic energy. The vibrating atoms having gained this kinetic energy now vibrate more. The resulting increase in the average vibration kinetic energy is rise in temperature.
Movement of charge carriers in any medium must necessarily be subject to such collisions causing loss of kinetic energy and generating heat in the medium. This heating of the medium due to the passage of charge carriers is a general property of all materials and is due to the resistance offered by the material to the flow of charge. The resistance of any material is measured as the potential difference required per unit current in that material. Hence the resistance (R) is determined as:
Where (V) is the applied potential difference and (I) the current in the material It should be noted that all materials require to have a potential difference applied in order to maintain an electric current in the material. Consequently all materials have resistance. Some materials become more heated than others despite the same rate of...

...Physics
Practical Report:
Experiment: Ohmic Resistance and Ohm’s Law
Patrick Doan
Mr Sadowsky
11 PHYS 71
12/9/08
Table of contents
1.0 Aim 1
2.0 Hypothesis 1
3.0 Materials 1
4.0 Method 2
5.0 Results 3
- 5.1 Qualitative Observations 3
- 5.2 Data 3-4
6.0 Discussion 5
7.0 Conclusion 6
8.0 Bibliography 7
9.0 Acknowledgements 7
1.0 Aim:
To find out how current, voltage and resistance in a circuit are related, also to discover the relationship known as ‘Ohm’s Law’.
2.0 Hypothesis:
In this experiment, conductors are used. Conductors which obey Ohm’s Law are called Ohmic conductors. Thus, for an ohmic conductor, a graph of V (Voltage) verses I (Current) is a straight line passing through the origin. A conductor that does not obey Ohm’s Law is called a non-ohmic conductor.
Ohm’s Law:
3.0 Materials:
• Power Pack 12V
• Voltmeter
• Light bulb
• 9 Alligator clips
• Ammeter
• Test tube
• Switch
• Multimeter
Patrick Doan 1
4.0 Method:
1. Collect all equipment and make sure the surface is clean and not wet
2. Wrap the nichrome wire around the test-tube to form a coil
3. Use the multimeter to measure the resistance of the light bulb
4. Connect the power pack to the power point but do not switch it on
5. Set up a series circuit...