Resistor is a component which is related to resistance. Simply we use it to limit the current flow of electricity.
Resister use with circuit to control the current to main components like valves or transistors. Like if we want to power the3V bulb from a 12V battery, we can use a proper resistor for it. The value of resistor display as ohms.
eg – like 1ohms, 100, 22 ohms,100, 1000,100k etc.
Anatomy of resistors –
Generally, there is resistance in various materials, and those exhibiting higher resistance are used to produce resistors. Carbon is widely used here. Accordingly, there are many types, such as carbon, wire wound, metal oxides, and metal films.
Additionally, there are two categories: fixed and variable.
Fixed resistors – Produce only for one value.
Variable resistors – Can be changed for a variety of values.
Fixed resistors
Carbon Resistor – Made primarily of carbon. It is small and is only produced for low power ratings. The resistance value can vary by about 5%. Widely used in electrical circuits.
Metal films have an accuracy value that is higher than carbon types, it is about 1% or 2%. They are often used in meters and precision time circuits where very accurate values are required.
Wire Wound – Manufactured using a special type of wire called resistance wire and is larger. It is suitable for higher power applications. Provides support for very high temperatures. These are widely used in power supply, television, and audio amplifier systems.
Additionally, there is a type called Fusible Resistor. These are used for circuit protection, and if excessive current tries to pass through beyond their rating value, they will destruct, thereby protecting the circuit.
Variable resistors – This resistor has a rotating spindle. When we rotate it, we can change the resistance of the output pins.
eg -Volume controls, presets.
Volume controls-
Power and resistors –
When current flows through a resistor, it is subjected to a limitation due to the resistance present in it. These causes increased heat on it. maximum amount of heat that can be safely used is indicated by the amount of watt. The resistor should always be used with a value greater than this amount. Otherwise, it will be destroyed due to excessive heating.
Power of resistors display as watts(W), like 0.25W, 1W, 3W, 10W etc.
Use this formula, and you can find the minimum power of the resistor.
P = V*I