Resistance is nothing but the opposition.Electricity is the flow of charges a type of force will exist in the conductor to oppose this flow of charges known as RESISTANCE. This type of force (RESISTANCE) is useful.. How it is used???? it is used to limit the flow of current. If we want only particular amount of current to be flown in to the destination then we can vary these resistance to control the flow of current.The resistance of a material is given by ohm (Ω).The resistance is measured using OHM METER.
The resistance of an object is defined as the ratio of voltage across it to current through it:
RESISTORS:
Naturally every material will have resistance in it so it can be used. If we want more to increase the resistance property of a material we can use materials called RESISTORS.These resistors will provide the necessary resistance to the materials.The below table gives the specifications for resistors
| Color | 1st band | 2nd band | 3rd band (multiplier) | 4th band (tolerance) | Temp. Coefficient |
|---|---|---|---|---|---|
| Black | 0 | 0 | ×100 | ||
| Brown | 1 | 1 | ×101 | ±1% (F) | 100 ppm |
| Red | 2 | 2 | ×102 | ±2% (G) | 50 ppm |
| Orange | 3 | 3 | ×103 | 15 ppm | |
| Yellow | 4 | 4 | ×104 | 25 ppm | |
| Green | 5 | 5 | ×105 | ±0.5% (D) | |
| Blue | 6 | 6 | ×106 | ±0.25% (C) | |
| Violet | 7 | 7 | ×107 | ±0.1% (B) | |
| Gray | 8 | 8 | ×108 | ±0.05% (A) | |
| White | 9 | 9 | ×109 | ||
| Gold | ×10−1 | ±5% (J) | |||
| Silver | ×10−2 | ±10% (K) | |||
| None | ±20% (M) |
To remember the order of Resistors colour there is a phrase:
BBROYOFGREATBRITAINHADVERYGOODWIFE
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