RESISTOR
Hello everybody Today our article is about RESISTOR in this article we will Discuss that how it works and how to read it color coding.
Resistor is an electrical component that is use to reduces the electric current. The ability to reduce current is known as Resistance and is measure in unit of ohm (symbol Ω ).
Resistors may be fixed or variable,
both controlling the flow of current differently.
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits.(source wikipedia)
A resistor is an electrical segment that cutoff points or controls the stream of electrical present in an electronic circuit. Resistors can likewise be utilized to give a particular voltage to a dynamic gadget, for example, a transistor.
Resistors may be fixed or variable,
both controlling the flow of current differently.
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits.(source wikipedia)
A resistor is an electrical segment that cutoff points or controls the stream of electrical present in an electronic circuit. Resistors can likewise be utilized to give a particular voltage to a dynamic gadget, for example, a transistor.
SYMBOL :
 | Resistor | Resistor reduces the current flow. |
 | Resistor | |
 | Potentiometer | Adjustable resistor - has 3 terminals. |
 | Potentiometer | |
 | Variable Resistor / Rheostat | Adjustable resistor - has 2 terminals. |
 | Variable Resistor / Rheostat | |
 | Trimmer Resistor | Presest resistor |
 | Thermistor | Thermal resistor - change resistance when temperature changes |
 | Photoresistor / Light dependent resistor (LDR) | Changes resistance according to light |
some old and new symbol of resistor
The symbol used in schematic and electrical drawings for a Resistor can either be a “zig-zag” type line or a rectangular box.
RESISTOR MADE UP OF:
The resistor is made up of following methods:
CARBON RESISTOR:
- It is made up of carban or graphite paste.
- FILM AND CERMET RESISTOR:
It made up of conductive metal oxide paste.
- WIRE WOUND RESISTOR :
- Another type of resistor, called a Wirewound Resistor, is made by winding a thin metal alloy wire (Nichrome) or similar wire onto an insulating ceramic former in the form of a spiral helix similar to the film resistor above.
OHM LAW:
The current through in resistor is inversely proportional to its resistance and directly proportional to the voltage across it. Well it is known as OHM LAW.
OR
The resistor current C is equal to the voltage V accross it and divided by its resistance R
mathematically it is written as:
The resistor's power consumption P is equal to the resistor's current
times the resistor's voltage V :
P = I × V
The resistor's power consumption P is equal to the square value of the resistor's current
times the resistor's resistance R :
P = I 2 × R
The resistor's power consumption P is equal to the square value of the resistor's voltage V
divided by the resistor's resistance R :
P = V 2 / R
Rtotal (EQUIVALENT RESISTANCE) MEASURE :
Resistors in parallel
The total equivalent resistance of resistors in parallel RTotal is given by:
So when you add resistors in parallel, the total resistance is decreased.
Resistors in series
The total equivalent resistance of resistors in series Rtotal is the sum of the resistance values:
Rtotal = R1+ R2+ R3+...
So when you add resistors in series, the total resistance is increased.
RESISTOR COLOR CODE:
The resistance of resistor and its tolerance are marked on resistor with color code band which is donoted by its value.
There are 3 types of color codes:
- 4 bands: digit, digit , multiplier, tolerance.
- 5 bands: digit, digit, digit , multiplier, tolerance.
- 6 bands: digit, digit, digit , multiplier, tolerance, temperature coefficient.
| 1st Digit | 2nd Digit | 3rd Digit | Multiplier | Tolerance | Temperature Coefficient | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 4bands | 1 | 2 | 3 | 4 | ||||||||
| 5bands | 1 | 2 | 3 | 4 | 5 | |||||||
| 6bands | 1 | 2 | 3 | 4 | 5 | 6 | ||||||
| Black | 0 | 0 | 0 | ×100 | ||||||||
| Brown | 1 | 1 | 1 | ×101 | ±1% | 100 ppm/ºK | ||||||
| Red | 2 | 2 | 2 | ×102 | ±2% | 50 ppm/ºK | ||||||
| Orange | 3 | 3 | 3 | ×103 | 15 ppm/ºK | |||||||
| Yellow | 4 | 4 | 4 | ×104 | 25 ppm/ºK | |||||||
| Green | 5 | 5 | 5 | ×105 | ±0.5% | |||||||
| Blue | 6 | 6 | 6 | ×106 | ±0.25% | 10 ppm/ºK | ||||||
| Violet | 7 | 7 | 7 | ×107 | ±0.1% | 5 ppm/ºK | ||||||
| Grey | 8 | 8 | 8 | ×108 | ±0.05% | |||||||
| White | 9 | 9 | 9 | ×109 | ||||||||
| Silver | ×10-2 | ±10% | ||||||||||
| Gold | ×10-1 | ±5% | ||||||||||
| None | ±20% |
Resistance calculation of 4 bands resistor
R = (10×digit1+digit2)×multiplier
Resistance calculation of 5 or 6 bands resistor
R = (100×digit1+10×digit2+digit3)×multiplier
TYPES OF RESISTOR :
| Variable resistor | Variable resistor has an adjustable resistance (2 terminals) |
| Potentiometer | Potentiometer has an adjustable resistance (3 terminals) |
| Photo-resistor | Reduces resistance when exposed to light |
| Power resistor | Power resistor is used for high power circuits and has large dimensions. |
| Surface mount
(SMT/SMD) resistor
| SMT/SMD resistors have small dimensions. The resistors are surface mounted on the printed circuit board (PCB), this method is fast and requires small board area. |
| Resistor network | Resistor network is a chip that contains several resistors with similar or different values. |
