What is Mean by Electrical Resistor
Resistor is a passive component, and it has two terminals. Resistors provide resistance to the circuit to reduce electrical current, to divide voltage, to adjust signal levels. Electrical resistors are also used in controlling electrical motors, but these are high power resistors which dissipate many watts of power.
Resistors are mainly used to reduce electrical current flow or to reduce the value of voltage in electrical circuit. Resistor are made from copper wire which Is wound around the ceramic rod and the outer [art of the resistor is coated with insulation.
Note
Definition of Electrical Voltage: the difference of potential difference between two points is voltage. It is used for powering motors, lights etc. It is measured in volts which is denoted by (V). It is also used to find electric current in the circuit.
Definition of Electrical current: electric current is the flow of charges in the conductor. It is measured in amperes which is denoted by (A). It is defined as the rate at which the charges flow in a surface.
Definition of Copper metal: copper is a material used mainly in electrical wiring, plumbing, motor winding and industrial machines. Definition of Electric circuit: it is path which allows electric current to pass. The source of the circuit is a battery, or it may be a generator and load may be a light bulb, motors etc. It is completed by closed loop. If the loop is not completed, then the circuit will be open. Electric circuits are classified in two types of series and parallel circuit.
What is Mean by Electrical Resistance
The measure of the materials that oppose the flow of electric current in a circuit is resistance. It is measured in ohm. The resistance of the materials depends upon different factors such as temperature, length and cross-sectional area. When temperature increases the resistance of the materials also increases and when temperature decreases the resistance of the materials also decreases. Resistance is directly proportional to the length of the materials and inversely proportional to the area.
The resistance is measured by the help of ohm law, which says that the current in the circuit is directly proportional to the voltage and inversely proportional to the resistance.
Formula is.
V = IR
to find the resistance the formula will be.
R = V / I
to find current the formula will be.
I = V/R
Here V represents voltage, R represents resistance, and I represents current.
SI unit of Electrical Resistor
The SI unit of resistor is ohm, and it is denoted by a symbol (Ω).
Symbol of Electrical Resistor
Resistor has two terminal which is connected to the electrical circuit.
Types of Electrical Resistors
(what is Mean by Electrical resistor)
Resistors have different shapes and sizes. Resistor may be standard, static or variable resistors.
Two main types of resistors are.
- Linear
- Nonlinear
What is Linear resistors
(what is Mean by Electrical resistor)
Linear resistors are those resistors whose value changes with the temperature and applied voltage. Most of the resistors are linear because when the current flows in it the voltage drops occur. Linear resistors are divided into two types which are fixed resistor and variable resistors.
What is Fixed resistors
Fixed resistors are those resistors which have fixed value that the value cannot be changed. It Is the most widely used resistors. These resistors are used in the electronic circuit. Different types of fixed resistor are.
- Corbon composition resistor: it is a type of fixed resistor which is used to limit the flow of current in the electric circuit. It is constructed from carbon powder and binder of clay or resin. The carbon powder is a conductor while the binder is insulator.
- Wire wound resistor. it is used to limit the flow of current in the circuit. It is constructed from a conductive wire which is wound around the nonconductive core. The resistance of the wire can vary between 1 to 1 mega ohm.
- Thin film resistor: thin film resistor is made from the thin film resistive layer, which is placed on the top of ceramic base. Its thickness is very thin. It has a better temperature coefficient which makes them useable in different applications.
- Thick film resistor: thick film resistor is made from the thick film resistive layer, which is placed on the top of ceramic base. Its thickness is 100 times that of the thin film resistor. Its accuracy is less as compared to thin film resistor. Its resistance can vary from 1 to 100 mega ohm.
What are Variable resistors
Variable resistors are the resistors of which the value can be changed or can be adjusted either mechanically or electrically. It is an electromechanical transducer which works by sliding contact over the resistive elements. When variable resistor is used as a potential divider then is use three terminal and known as potentiometer while when use two terminals then known as variable resistor and called as rheostat. Electrically controlled variable resistors exist and are controlled electrically.
Different Types of variable resistor
- Potentiometer: potentiometer is piece of wire which is connected to the battery or cell. This wire is divided into several pieces which are connected end by end by a metal strip. The variable resistance is connected to the circuit which varies the current flow in the wire. To measure the potential difference, change the resistance manually.
- Rheostat: it is a variable resistance which is used to measure electric current flow by changing the resistance.
- Trimmer resistor: the resistance of the trimmer resistance changed by turning a screw. It is used in the circuit because its resistance can be adjusted for the circuit performance.
What is Nonlinear resistor
Nonlinear resistors are those resistors whose value is changed when change comes in temperature or applied voltage. Nonlinear resistors are not depended in ohm law. Different types of nonlinear resistors are followed.
- Thermistor: the resistance of the thermistor changes with temperature because thermistor is very sensitive to the temperature. It is a passive device used in a circuit to measure temperature.
- Varistors: the resistance of the varistor changed with the applied voltage. It is also called a voltage-depended on resistor. Its resistance increases when voltage decreases, and the resistance decreases when voltage decreases. It is used to protect circuits from over voltage.
- Photo resistors: it is a passive component. Its resistance changes with respect to light. The resistance of photo resistors decreases when the intensity of light increases. It is used in light sensitive detector circuits.
What is Resistor color coding
|
|
Band 1 | Band 2 | Band 3 | Band4 | Band 5 | Band 6 |
| Color | 1st | 2nd | 3rd | Multiplier | Tolerance | TCR (10-6/k) |
| Black | 0 | 0 | ×100 | ±250 | ||
| Brown | 1 | 1 | 1 | ×101 | ±1% | ±100 |
| Red | 2 | 2 | 2 | ×102 | ±2% | ±50 |
| Orang | 3 | 3 | 3 | ×103 | ±0.05% | ±15 |
| Yellow | 4 | 4 | 4 | ×104 | ±0.02% | ±25 |
| Green | 5 | 5 | 5 | ×105 | ±0.5% | ±20 |
| Blue | 6 | 6 | 6 | ×106 | ±0.25% | ±10 |
| Violet | 7 | 7 | 7 | ×107 | ±0.1% | ±5 |
| Grey | 8 | 8 | 8 | ×108 | ±0.01% | ±1 |
| White | 9 | 9 | 9 | ×109 | ||
| Gold | ×10-1 | ±5% | ||||
| Silver | ×10-2 | ±10% | ||||
| Pink | ×10-3 |
This resistor calculator will help you to find the value, tolerance, and temperature coefficient of the color-coded resistor of any bands simply select the bands colors. It can calculate the maximum and minimum values which is based on tolerance ratio.
Electrical Resistors in series Connection
When the current through all the resistors is same then the resistor is said to be in series. In series connection the resistors are connected in head to tail pattern that as the head of one resistor is connected to the tail of the other resistor. Total resistance of the circuit is the sum of the of the individual resistance. The current in parallel connection is the same while voltage is different.
Formula for resistors in series
Electrical Resistors in parallel Connection
When the terminals of the resistors are connected to the same two nodes then the connection is said to be in parallel. Voltage in parallel connection is same while current is different.
Formula for resistors in parallel
Application of Electrical Resistor
(what is Mean by Electrical resistor)
Resistors are used for different purposes in electronic devices such as adjusting signal level, reducing current flow, dividing voltages, biasing active elements, terminating transmission line, etc. Resistors are used to create simple circuit e.g., voltage divider, pull up and pull-down resistors, RC filters and current limiter.
- If high sensitivity, accurate measurement is required then wire wound resistor is used
- Photoresistors are used in flame detectors, photographic devices etc.
- Resistors are used in voltmeter.
- Resistors are used in temperature controlling.
- It is used in digital multimeter, telecommunication and amplifiers.
- It is also used in modulation, demodulation and transistors.
Frequently asked questions FAQs
Q1: What is a resistor?
Ans: resistors are passive components, and they have two terminals.
Q2: why is resistor used in a circuit?
Ans: it is used in a circuit to limit the flow of current or to divide voltage.
Q3: What are the two main types of resistors?
Ans: the two main types of resistors are.
- Linear resistor
- Nonlinear resistor
Q4: what is the SI (system international) unit of resistor?
Ans: the system international (SI) unit of resistor is ohm (Ω).
Q5: name some of the resistive materials?
Ans: the resistive materials are, rubber, glass, wood, mica etc
Q 6: What are the types of fixed resistors?
Ans: the types of the fixed resistor are.
- Wire wound resistors.
- Thin film resistors.
- Carbon composition resistors.
Q 7: What is a thermistor?
A thermistor is a type of resistor which is used to measure temperature.
See Also:
