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Resistor
As you know the resistor is an inevitable part of a circuit. It is meant for reducing the current and voltage in the circuit parts. Resistors are identified using the standard colour code chart. A simple trick can be used to identify the resistor value range. The third colour band on the body of the resistor represents the multiplier value. So by identifying the third colour, it easy to know the value in range.
Maximum power handling capacity of Resistors is
¼ Watt Max. 50mA, ½ Watt Max. 70mA, 1 Watt Max. 100mA, 2 Watt Max. 140mA,20 Watt Max.440mA
Resistor Color code
Colour
Ring 1
Figure 1 Ring 2
Figure 2 Ring 3
Multiplier Ring 4
Tolerance
Black 0 0 1
Brown 1 1 10
Red 2 2 100
Orange 3 3 1000
Yellow 4 4 10000
Green 5 5 100000
Blue 6 6 1000000
Violet 7 7 X
Grey 8 8 X
White 9 9 X
Gold - - 1/10 +/- 5%
Silver - - 1/100 +/- 10%
Body colour - - X +/- 20%
How to identify a resistor
Suppose the Resistor has the following colour rings
Ring 1 Yellow
Ring 2 Violet
Ring 3 Orange Multiplier
Ring 4 Gold Tolerance
Add values
Yellow 4 + Violet 7 = 4+7 = 47
Orange 1000
So 4+7x1000 = 47x1000 = 47000 Ohms .That is 47000 / 1000 = 47K
Three colour resistor
Ring 1 Green 5
Ring 2 Black 0
Ring 3 Gold 1/10
Add values
Green 5 + Black 0 = 5+0 = 50 x 1/10 = 5 Ohms
Color code of Resistors commonly used in projects
Brown-Black-Red 1K Orange-Orange-Orange 33K Orange-White-Yellow 390K
Brown-Green-Red 1.5K Yellow-Violet-Orange 47K Yellow-Violet-Yellow 470K
Red-Red-Red 2.2K Green-Blue-Orange 56K Green-Blue-Yellow 560K
Red-Grey-Red 2.8K Blue-Grey-Orange 68K Brown-Black-Green 1M
Yellow-Violet-Red 4.7K Brown-Black-Yellow 100K Brown-Black-Blue 10M
Brown-Black-Orange 10K Brown-Red-Yellow 120K
Brown-Red-Orange 12K Brown-Green-Yellow 150K
Brown-Green-Orange 15K Red-Red-Yellow 220K
Red-Red-Orange 22K Red-Violet-Yellow 270K
Easy identification of Resistor
It is easy to identify the value range of a Resistor through the Third color
Third Colour Value
Gold 1 to 9 Ohms
Black 10 to 99 Ohms
Brown 100 to 999 Ohms
Red 1 K To 9.9K
Orange 10K to 99K
Yellow 100K to 999K
Green 1M to 9.9M
Blue 10M to 99M
How the Disc capacitor is identified?
In Disc capacitors, only a number is printed on its body so it is very difficult to determine its value in PF, KPF, uF, n etc. In some capacitor, its value is printed in uF eg.0.1 in some others EIA code is used e.g. 104. The following tricks can solve the problem.
1. One or two numbers on the capacitor represents value in PF e.g. 8 = 8PF
2. If the third number is zero, then the value is in P e.g. 100 = 100PF
3. If the capacitor has three numbers and the third number is not a zero, it represents the number of zeros after the first and second digits e.g. 104 = 10 – 0000 PF
4. If the value is obtained in PF, it is easy to convert it into KPF or uF
PF / 1000 = KPF or n
PF / 10, 00000 = uF
For example, if the capacitor is 104, then it is 10-0000 PF or 100 KPF or n or 0.1 uF
5. Conversion formula
n x 1000 = PF PF/1000 = n PF/1,000,000 = uF uF x 1,000,000 = PF uF x 1,000,000/1000 = n n=1/1,000,000,000F uF = 1/ 1000,000 F
6. English letter below the value represents tolerance e.g. 473 = 473 K K
If the capacitor has four digits and the fourth digit is a zero, then the value is in PF. E.g. 1500 = 1500PF
7. If a number is represented with a decimal, the value is in uF. E.g. 0.1 = 0.1 uF
8. If an alphabet is given below the digits, it represents a decimal and the value is in KPF or n
E.g. 2K2 = 2.2 KPF
9. If the values are given with slashes, the first digit represents value in uF, second its tolerance and third
its maximum voltage rating E.g. 0.1/5/800 = 0.01 uF / 5 % / 800 Volt.