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ELECTRO-TECHNIQUE 1
COMPONENT CODING AND MULTIMETER
OBJECTIVE
1. To acquaint students with the skill to read resistor and capacitor values based on color
code and digital/alphabet code.
2. To familiarize students in using multimeter to measure resistance, voltage and current
as a basic tool in measurement.
3. To make students understand how to do real connections or wiring in the laboratory
based on the given schematic diagram using breadboard to easily connect components
together to build circuits.
INTRODUCTION
RESISTOR CODING
The color code technique is used to show resistance values of carbon resistors without
having to measure it. In this technique color bands are printed on the resistor. The
procedure for determining the resistance of a color-coded resistance is described in Table
1. The first two bands determine the first two digits of the resistor value, while the third
band determines the power of 10-multiplier. For the resistor with value less than 10  the
third band is either silver or gold. The forth band is the percent tolerance for the chosen
resistor. If resistors have only three bands, it means the forth band has no color.
Sometimes a fifth band is employed for some high precision resistor where the first three
bands represent the significant digit. The forth band is the multiplier while the fifth band
is the tolerance. In the other case, for some standard 4-band code, a fifth band may
indicate the manufacturer’s special code for some physical characteristic or failure rate of
the component.
For increasing wattage, the size of resistor will increase accordingly. The larger sized
resistors from about 5 W and up or wire winding resistors are not color-coded but are
using digital and alphabet code printed on its body. In writing the value of resistors: k
stands for multiplier “kilo” and M for multiplier “mega”. The alphabet written after the
resistor value shows the tolerance: F = 1%, G = 2%, J = 5%, K= 10% and M = 20%.
Resistance should never be measured in a live network due to the possibility of damaging
the meter with excessively high currents and obtaining readings that have no meaning. In
a constructed circuit, to measure a single resistance value, just take off one end of its
terminal to avoid the effect of other resistances in the circuit. This applies in the same
manner to the other components such as capacitor and inductor.
The standard code is adopted by manufacturer through their trade association, the
Electronic Industries Association (EIA).
Color
4th Band
3rd Band
(Tolerance)
(Multiplier)
1st Band
(1st Significant Digit)
2nd Band
(2nd Significant Digit)
0
1
2
3
4
5
6
7
8
9
-
0
1
2
3
4
5
6
7
8
9
-
1
101
102
1 03
104
105
106
107
108
109
0.1
0.01
5%
10%
-
-
-
20%
Black
Brown
Red
Orange
Yellow
Green
Blue
Violet
Grey
White
Gold
Silver
No
Color
1%
2%
3%
4%
Table 1.1: Resistor color coding
Figure 1.1: Reading resistor color coding
Example 1:
The value of this resistor is 25 x 101±
10% = 250± 10% ohms
Minimum value – 225 
Maximum value – 275 
Example 2:
R33F = 0.33 ±1% 
4k7 = 4.7 x 103 
10R0 = 10 
200R = 200 
50M = 50 x 106 
6k8J = 6.8 x 103  ±5%
R39 = 0.39 
2k2M = 2.2 x 103 ±20%
1R0 = 1 
CAPACITOR CODING
Same as resistors, most of the capacitors have their nominal value printed directly on
them using digital/alphabet code according to the EIA coding system. This code is
generally given in picofarads (pF), which means that we need to manipulate the value if
we want the value in microfarads (F) or nanofarads (nF). Some capacitors have polarity
(positive and negative) which must be connected according to their polarity in order for
the capacitor to operate such as the electrolytics capacitors. Normally the negative leg of
electrolytics capacitor could be recognized by the white stripes at the body and/or the
negative leg is shorter then the positive leg.
Some types of capacitors are shown in Figure 1.2 below.
Figure 1.2: Different types of capacitors construction
Example 3:
Capacitor marked 104 has value of 10 with 4 zeroes after it, or 100,000pF (equivalent to
100 nF or 0.1 F)
Capacitor marked 681 = 68 with single zero or 680 pF
Capacitor marked 472 = 47 with 2 zeroes or 4700 pF (equivalent to 4.7nF)
Alternatively, the value may be given directly in nanofarads with three significants digits
but the thirds generally ‘0’. In this case there is generally also a small ‘n’ which can be
used in place of decimal points.
Example 4:
Capacitor marked 220n has 220nF capacitances (equivalent to 0.22F)
Capacitor marked 3n3 has 3.3nF capacitances (equivalent to 3300pF)
Some of the capacitors have a capital letter to indicate their tolerance rating. Below is
capacitor tolerance marking codes:
F
 1%
G
 2%
J
 5%
K
 10%
M
 20%
Z
-20%, +80%
Example 5:
104K = 0.1F  10%,
4n7J = 4.7nF  5%
BREADBOARD
When building a "permanent circuit" the components can be "grown" together (as in an
integrated circuit), soldered together (as on a printed circuit board), or held together by
screws and clamps (as in house wiring). In lab, we want something that is easy to
assemble and easy to change. We also want something that can be used with the same
components that "real" circuits use. Most of these components have pieces of wire or
metal tabs sticking out of them to form their terminals.
A breadboard is used to make up temporary circuits for testing or to try out an idea. No
soldering is required so it is easy to change connections and replace components. Parts
will not be damaged so they will be available to re-use afterwards.
Figure 1.3: Front look of a typical small breadboard used in the laboratory
The breadboard has many strips of metal (usually copper) which run underneath the
board.
Figure 1.4: The metal strips layout
When wiring, it is important to keep your work neat! This will save time in debugging
when your circuit doesn’t work. Here are some tips: Keep your wires short, do not loop
wires over the chip, use the bus lines for Ground or a DC supply voltage (e.g. VCC) and
sometimes to get cleaner signals, short the metal base of the breadboard to the circuit’s
ground.
MULTIMETER
Multimeter is a basic tool in electric and electronic fields. It is a multipurpose device to
measure voltage, current and resistance. Basically there are two types of multimeter used
either in the education or industrial field based on the electronic circuits inside them:
analog and digital meters. The analog meter, broadly known as VOM (volt-ohmmiliammeters) uses a mechanical moving pointer which indicates the measured quantity
on a calibrated scale. It requires the user a little practice to interpret the location of the
pointer. The digital meter broadly known as DMM (digital multimeter) used number or
numerical display to represent the measured quantity. It has high degree of accuracy and
can eliminate usual reading errors compared to the analog meters. Students should be
adept at using both meters throughout their studies.
Resistance Measurement: For VOM always reset the zero-adjust whenever you change
scales. In addition always choose the range setting that will give the best reading of the
pointer location. As an example, to measure a 500- resistance, choose function switch
resistance with a range setting of X 1k. Finally do not forget to multiply the reading by
the proper multiplication factor. If you are not sure about the value always starts with the
highest range and going downwards until appropriate scale is chosen. For DMM
remember that any scale marked “k” will be reading in kilo-ohms and any with
“M”scale in mega-ohms and so on. There is no zero-adjust on a DMM meter but make
sure that the resistance reads zero when shunting both leads. Polarity does not concern in
resistance measurement. Either lead of the meter can be placed on either terminal end of
the component, it will be the same.
Voltage Measurement: When measuring voltage levels, make sure the meter is connected
in parallel with the element whose voltage is to be measured. Polarity is important
because the reading will indicate up-scale or positive reading for correct connection and
down-scale or negative reading if reverse connection of the meter test leads to the
resistor’s terminals. Therefore a voltmeter is not only excellent for measuring voltage but
also for polarity determination. Choose the correct function switch for example DCV to
measure dc voltage and turn to the range switch that has slightly bigger value than the
voltage to be measured.
Current Measurement: When measuring current levels, make a series connection between
the meter and the component whose current is to be measured. In other words, disconnect
the particular branch and insert the ammeter. The ammeter also has polarity marking to
indicate the manner they should be hooked-up in the circuit to obtain an up-scale or
positive measurement. For analog meter pay attention that reversing the polarity of the
meter may cause damage to the pointer. Again always start with higher range going
downwards to avoid damaging the instrument.
The connection of the multimeter to measure different electrical quantities is shown in
both schematic diagram and real wiring illustration in the laboratory in Figure 1.5.
R
Vs
V/
A
Figure 1.5(a): Schematic diagram
Figure 1.5(b): Real wiring diagram for illustration
EQUIPMENT/COMPONENT
Multimeter (1)
Adjustable DC power supply (1)
Resistor (1/4 W) – 1 k , 2.2 k, 4.7 k, 15 k, 680 ,
33 , 1 , 27 k, 39 k, 270 k, 3.9 k
Potentiometer – 10 k
Breadboard (1)
**For non-measured resistor and capacitance values students are strictly required to
complete the answers before the lab session. Otherwise they will be forbidden from
participating the session.
PROCEDURE
PART A: READING RESISTOR BY COLOR CODING
Determine the nominal value or color bands of a particular resistor based on color coding
technique for each case given in Table 1.2 below. Check your answers with the measured
values in the laboratory.
COLOR BAND
No.
Band 1
Band 2
Band 3
Band 4
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
orange
orange
brown
red
orange
brown
red
orange
white
green
violet
white
black
violet
black
red
orange
orange
orange
gold
orange
gold
gold
gold
gold
gold
no color
gold
Nominal
Value
Measured
Value ()
Within
Tolerance?
YES/NO
1k ± 5%
680 ± 5%
4.7k ± 5%
2.2k ± 5%
Table 1.2: Exercise for determining resistor values by color coding and measurement
PART B: READING RESISTOR
CODING
AND CAPACITOR BY DIGITAL/ALPHABET
Determine the nominal value of a particular resistor based on digital/alphabet coding
technique for each case given in Table 1.3 below.
DIGITAL/ALPHABET CODE
3k9
1R0
2R2
8M5
R56
NOMINAL VALUE (in ohm)
Table 1.3(a): Exercise for determining resistor values by digital/alphabet coding
DIGITAL/ALPHABET CODE
33J
15
104
220n
3n3J
103
103Z
NOMINAL VALUE( in nanofarad)
Table 1.3(b): Exercise for determining capacitor values by digital/alphabet coding
PART C: USING MULTIMETER TO MEASURE RESISTANCE, VOLTAGE AND
CURRENT
EXERCISE 1:
Using the supplied equipments/components in the laboratory, hook-up the series resistive
circuit as in Figure 1.5. As a common practice, always measure the actual value of the
resistors used in the circuit and set the source value using multimeter to reduce errors
from the expected results. Perform the following instructions;
1. Measure currents I1 and IT. Should they be the same? Give your reason.
Answer:
I1 = ________ mA
IT = ________ mA
Comment:
________________________________________________________________________
________________________________________________________________________
2. Measure voltage drop across resistor R1.
Answer:
VR1 = ________ V
3. Measure voltage drop across the combination resistors R2 and R3.
Answer:
VR2R3 = ________ V
4. Disconnect the power supply and measure the total resistance in the circuit, Req.
Answer:
Req = ________ 
I1
R1
1k0
R2
2k2
Vs=10 V
R3
4k7
Measured values:
R1 = ________ 
R2 = ________ 
R3 = ________ 
IT
Req
Figure 1.6: Simple series resistive circuit
EXERCISE 2:
Modify the previous series circuit connection to reconstruct a parallel resistive
connection as in Figure 1.6. Perform the following instructions;
I1
Vs=10 V
R1
1k0
I2
I3
R2
2k2
R3
4k7
IT
Req
Figure 1.7: Simple parallel resistive circuit
1. Measure currents I1, I2 and I3 as indicated in the above diagram using miliammeter.
Answer:
I1 = ________ mA
I2 = ________ mA
I3 = ________ mA
2. Measure the total current, IT. Do you get the same value as in Exercise 1?
Answer:
IT = ________ mA
Comment:
________________________________________________________________________
________________________________________________________________________
3. Use the ohmmeter to measure the equivalent resistance Req of this circuit. Does the
result equal to the one measured in Exercise 1?
Answer:
Req = ________ 
Comment:
________________________________________________________________________
________________________________________________________________________
4. Measure voltage drop across R1, R2 and R3. What can you conclude from these
results?
Answer:
VR1 = ________ V
VR2 = ________ V
VR3 = ________ V
Comment:
________________________________________________________________________
________________________________________________________________________
EXERCISE 3:
Now we should be ready to increase the complexity of the circuit by trying to construct a
series-parallel circuit as in Figure 1.7. In this exercise we also achieve some adjustable
variables using potentiometer and adjustable power supply to see their effects on the
circuit. Perform the following instructions;
I1
R1
1k0
x
I5
R2
2k2
Io
Vs
Ro
10k0
R3
4k7
R4
15k0
R5
680R
IT
Req
y
Figure 1.8 Series-parallel resistive circuit
Measured values:
R1 = ________ 
R2 = ________ 
R3 = ________ 
R4 = ________ 
R5 = ________ 
1. Set the adjustable DC power supply Vs to 15 V and the potentiometer, R2 to 500 .
2. Then measure currents I1 and Io. Change Ro to 5 k and again measure I1 and Io. Give
comment on both results.
Answer:
R2 = 500 :
R2 = 5 k:
I1 = ________ mA
I1 = ________ mA
Io = ________ mA
Io = ________ mA
Comment:
________________________________________________________________________
________________________________________________________________________
3. Measure the voltage drop across R4 and R5 using the previous settings of the
potentiometer and power supply (Vs = 15V, Ro = 5k).
Answer:
VR4 = ________ V
VR5 = ________ V
4. Adjust the power supply until voltage across point x-y reads 8.5 V.
5. Measure the power supply voltage Vs.
Answer:
Vs = ________ V
6. Using the previous settings of Vs, adjust Ro until Io is equal to 5 mA. Read the value
of Ro and I5 and IT.
Answer:
Ro = ________ 
I5 = ________ mA
IT= ________ mA
APPENDIX A: SANWA ANALOG METER
Figure A1: Names of components
a) Precaution for safety measurement
i.
To ensure that the meter is used safely, follow all safety and operation instructions.
ii.
Never use meter on the electric circuit that exceed 3kVA.
iii.
Never apply an input signals exceeding the maximum rating input value.
iv.
Pay special attention when measuring the voltage of AC30Vrms or DC60V or more to avoid
injury.
v.
Always keep your fingers behinds the finger guards on the probe when making
measurements.
vi.
Before starting the measurement, make sure that the function or range properly set in
accordance with he measurement.
vii.
Be sure to disconnect the the test pins from the circuit when changing the function or range.
viii.
For details, please refer instruction manual.
b) Preparation for Measurement
c)
i.
Adjustment of meter zero position
ii.
Turn the zero position adjuster so that the pointer may align right to the zero position.
Range selection: Select a range proper for the item to be measured. Set the range selector knob
accordingly.
Measuring DCV
i.
ii.
iii.
Set the range selector knob to an appropriate DCV range.
Apply the black test pin to the minus potential of measured circuit and the
plus potential as in Figure A2.
Read the move of the pointer by V and A scale.
red test pin to the
Figure A2
d) Measuring DCV (NULL)
i.
ii.
iii.
iv.
Set the range selector knob to an appropriate range.
Turn the adjuster so that the pointer may align exactly to 0 by DCV scale.
Apply the black test pin to the negative potential side of the circuit and the red test pin to the
positive potential side as in Figure A3.
Read the move of the pointer by DCV scale.
Figure A3
e)
Measuring ACV
i.
Turn the range selector knob to an appropriate ACV range.
ii.
Apply the test leads to measured circuit as in Figure A4.
iii.
Read the move of the pointer by V and A scale. (Use AC 10V scale for 10V range only)
Note: Since this instrument employs the mean value system for its AC voltage measurement circuit,
AC waveform other than sine wave may cause error.
Figure A4
f)
Measuring DCA
i.
ii.
iii.
iv.
Connect the meter in series with the load.
Turn the range selector knob to an appropriate DCA range.
Take out measured circuit and apply the black test pin to the minus potential of measured
circuit and the red test pin to the plus potential as in Figure A5.
Read the move of the pointer by V and A scale.
Figure A5
g) Measuring Resistance ()
Precaution: Do not measure a resistance in a circuit where a voltage is present.
i.
ii.
iii.
iv.
v.
Turn the range selector knob to an appropriate  range.
Short the red and black test pins and turn the 0 adjuster so that the pointer may align exactly
to 0. (If the pointer fails to swing up to 0 even when the 0 adjuster is turned clockwise
fully, replace the internal battery with a fresh one.)
Apply the test pin to measured resistance as in Figure A6.
Read the move of the pointer by  scale.
Note: The polarity of (+) and (-) turns reverse to that of the test leads when measurement is
done in  range.
Figure A6