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The resistor is an electrical component that regulates or limits the flow of electrical current in an electronic circuit. There are different types of resistors we classified these resistors into two categories variable resistors and fixed resistors. Resistors can also be used to provide a specific voltage to activate a device such as a transistor. It is the most commonly used component in all types of electronic devices.
There are two types of resistors mainly and further divided into more types according to their functions.
A resistor whose value can be adjusted is called a variable resistor. Variable resistance is useful when we do not know what value of the resistor will be required in a circuit. By using pots as adjustable resistors we can set the right value while the circuit is working.
Different types of variable resistors are as follows.
The potentiometer is an ordinary variable resistor. A potentiometer has three terminals in which the resistance is manually varied to control the flow of low-power current. The potentiometer consists of three terminals. we can increase and decrease the resistance of the potentiometer to control the flow of electric current by rotating the nob.
A rheostat is also a variable resistor that is used to control the current. These variable resistors are able to change the resistance in a circuit without interruption. The structure of these resistors is almost the same as a potentiometer. Only two terminals are used even if these variable resistors have three terminals. Rheostats are often used as power control devices, for example, to control light intensity, to control the speed of motors, heaters, ovens, etc.
Presets are the small versions of standard variable resistors. They are designed to be mounted on circuit boards and adjusted only when the circuit is built however their value can be adjusted. Presets are available in vertical and horizontal shapes and styles. Different shapes of the Preset are shown in the given below figure.
