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variable resistor

Primary Information
Secondary Information

Definition

A variable resistor, also known as a potentiometer, is an electronic component whose resistance can be changed. It is made up of a resistive element, such as a wire, and a movable contact.

The resistance of the variable resistor is determined by the position of the movable contact. When the contact is close to one end of the resistive element, the resistance is low. When the contact is close to the other end, the resistance is high.

Variable resistors are used in a variety of electronic circuits, including dimmers, volume controls, and oscillators. They can also be used to measure voltage and current.

How can the word be used?

The number of students in the class is a variable."The variable resistor was used to control the brightness of the LED.

variable resistor

Different forms of the word

Noun: an electrical resistor whose resistance can be changed.

Adjective: of or relating to a variable resistor.

Etymology

The word "variable resistor" comes from the combination of the words "variable" and "resistor".

The word "variable" comes from the Latin word "variabilis", which means "changeable".

The word "resistor" comes from the Latin word "resistere", which means "to withstand".

The first recorded use of the word "variable resistor" in English was in the 19th century.

Question

When might you use a variable resistor?

AQA Science Exam Question and Answer

Question:

Explain the purpose and functioning of a variable resistor in an electric circuit. Provide an example of a real-world application where a variable resistor is used and its significance.

Answer:

A variable resistor, also known as a rheostat, is a component used in electric circuits to control the flow of electric current by changing its resistance. It consists of a resistive material with a sliding contact that can be adjusted along its length. By changing the position of the sliding contact, the total resistance in the circuit can be varied, thus regulating the current passing through it.

One real-world application of a variable resistor is in audio equipment, such as volume controls in radios, televisions, and amplifiers. In this context, the variable resistor allows users to adjust the output sound level by changing the resistance in the circuit. By altering the resistance, the amount of current passing through the audio signal can be controlled, resulting in louder or softer sound output.

The significance of variable resistors lies in their ability to fine-tune circuit performance and adapt devices to specific needs. They offer precise control over current and voltage, enabling the customisation of electronic devices for optimal functionality. In the case of audio equipment, variable resistors provide users with a convenient means to adjust sound levels to their preferences. Overall, variable resistors contribute to the versatility and usability of various electronic devices by allowing users to modulate electrical characteristics according to their requirements.