Resistors

1.Where can I buy resistors online?

Resistor boxes and other combination sets of resistors  can be bought online from online stores like Robocraze.

2. Where can I buy resistors near me (locally)?

Resistors are easily available in any electronic shops at your local city market.

3. Can I buy resistors in bulk?

Resistors are usually always sold as bulk as it isn't feasible to ship and sell individual resistors. So a bulk purchase of resistors is an economical option.
 

4. How to choose resistors online?

You can shoes the appropriate resistor by deciding on the value range, power rating, tolerance, etc. You can then cross check whether your requirements conform within the resistor specifications.
 

5. Define resistor specifications:

Resistance value: Resistance is the main measure of a resistor and it measure the opposition of electric flow, measured in ohms

Tolerance: Tolerance specifies the potential of deviation in error with respect to the resistance value

Power rating: Power rating specifies the power (voltage * current) the resistor can withstand 

Stray inductance: Stray inductance is a measure of the amount of unwanted inductance the resistor induces into the circuit

Surge rating: Surge rating is a measure of potential pulse in power the resistor can withstand for a short amount of time 

Maximum working voltage: Specifies the maximum voltage the resistor can handle without breaking down

6. What are the types of resistors?

Resistors come in a few types. The type you choose depends on your need and use case. Some of the types are

Carbon Composition Resistor: low cost, easy to construct resistors used for prototyping

Thermistor: Resistors who’s resistance value changes with temperature

Wire Wound Resistor: These resistors are used in high power applications

Variable Resistor: Resistors whose value can be varied by a knob

Varistor: Non linear resistors that do not obey ohm’s law

Light Dependent Resistor: Resistors whose resistance changes depending on the light intensity falling onto the resistor
 

7. How to identify the value of a resistor?

Value of a resistor can be identified using two ways

Using a multimeter: Keep the multimeter in resistance mode and put the probes across the resistor. Your multimeter should indicate the approximate resistance of the resistor

By observing the colour bands: Resistor Values in resistors are indicated using coloured bands that specifies meaning. You can refer to the image below on what each colour band across a resistor depicts. Most resistors are four band resistors, so you can ignore the 5 and 6 band resistor for now

For example, 1. If the colour code of a 4 band resistor is yellow, violet, red and gold it means

                           1st digit (yellow) -> 4

                           2nd digit (violet) -> 7

                           3rd digit (red) -> 100

                           4th digit (gold) -> 5%

                           Inference: 47 x 100  with 5% tolerance = 4700 ohm = 4.7 kohm resistor with 5% tolerance

                       2. If the colour code of a 4 band resistor is brown, black, brown and gold it means

                           1st digit (yellow) -> 1

                           2nd digit (violet) -> 0

                           3rd digit (red) -> 1

                           4th digit (gold) -> 5%

                           Inference: 10 x 10  with 5% tolerance = 100 ohm with 5% tolerance