Download AVOP-ELEKTRO-MEL-001

Tutorial: Mechanic - electrician
Topic: Technical training
II. class
Passive components – resistors 1
Prepared by: Melichařík Lubomír
Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002
je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.
Resistor
-
Passive electrical component
In an ideal case there is just one property
manifested in an electric circuit:
Electrical resistance
The reason for the inclusion of the resistor
in the circuit is:
reduce the size of the electric current
obtain a voltage drop.
The component is commonly referred to as
resistance, but the name used is a resistor.
Electrotechnical schematic of symbols:
Schematic of the resistor symbol used in Europe
Schematic of the resistor symbol used in USA and Japan
Schematic of the fixed adjustable resistor
symbol – resistance trimmer
Schematic of the continuously adjustable
resistor symbol - potentiometer
An Ideal Resistor should have a single parameter, i.e. its resistance and this
parameter should not be dependent on any external factors. According to
Ohm’s law, therefore, the current flowing through a resistor with resistance R
and the applied voltage U was equal to
On the contrary, the resulting voltage drop of the same resistor with a current I:
The power relationship:
the resistor gets hot, which means, that passing a current through it heats it.
If no resistor is used as a resistive heating element, the heat is lost.
Equivalent circuit of a real resistor
Real resistor is, however, made of real materials showing an electrical
resistance and has a definite geometry.
Parameters of resistors
-electrical resistance is in ohms
-series of preferred numbers E6, E12 or E24
-the most widely used number is E12
-contains the following 12 values, which are then multiplied by the square of
the tens: 1,0; 1,2; 1,5; 1,8; 2,2; 2,7; 3,3; 3,9; 4,7; 5,6; 6,8; 8,2
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R1 = 0,1 Ω
10R = 10J = 1 × 10¹ Ω
4M7 = 4,7 × 1MΩ =
4,7 × 106 Ω
k1 = 0k1 = 0,1 . 1 k Ω = 0,1 × 10³ Ω = 1 × 10² Ω = 100 Ω = 100R = 100J
222 = 22 . 102 Ω = 2200 Ω
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-maximum power is in Watts: Values for example 0,6 Watt; 1 Watt, 2 Watt, ...
-tolerance-resistance value of a resistor is given in a percentage(0,5 %; 1 %;
5 %; 10 %; 20 %)

Construction of a resistor-wire, carbon, wound, special.
Labelling of resistors
 The basic unit for labelling resistors is 1 Ω (1 ohm). The value of the resistor
is today often indicated by the stripe colour code. The colour coding used is
in accordance with the International code EIA-RS-279.
 Table of colour codes:
1.
stripe
2.
stripe
3.
stripe
Multiplier
Black
0
0
0
×10
0
Brown
1
1
1
×10
1
±1% (F)
100 ppm
0.1%;
Red
2
2
2
×10
2
±2% (G)
50 ppm
0.01%;
×10
3
15 ppm
0.001%;
×10
4
×10
5
±0.5% (D)
×10
6
±0.25% (C)
10 ppm
×10
7
±0.1% (B)
5 ppm
±0.05% (A)
Colour
Orange
Yellow
Green
Blue
Violet
3
4
5
6
7
3
4
5
6
7
3
4
5
6
7
Grey
8
8
8
×10
8
White
9
9
9
×10
9
Tolerance
Reliability
1%;
25 ppm
1 ppm
Gold
×0.1
±5% (J)
Silver
×0.01
±10% (K)
None
Temp.
coefficient
±20% (M)

Miniature Resistors
Power resistors

Resistance trimmers
Potentiometers
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1. What is a resistor?
2. What is the ideal resistor?
3. What is a real resistor?
4. Draw the schematic symbols used in
Europe.
5. Draw the schematic symbols used in USA
and Japan.
6. Draw a diagram of an ideal resistor and
write the basic calculation formulas.
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1. What are the parameters reported in the
resistor?
2. What are the basic designs of resistors?
3. What are the types of resistors?
4. What is the use of resistors?
5. What are the labels of resistors?
6. What are the characteristic properties of
resistors?


Václav Malina
Adrian Schommers
3-92608-32-5
Poznáváme elektroniku I.
Elektronika tajemství zbavená. ISBN