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question English réponse English
What type of resistor is called a rheostat?
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A two-terminal variable resistor is called a rheostat.
What is a rheostat used for?
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It is used to control the current in a circuit.
How does a rheostat vary the value of current?
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By sliding a contact along a resistive element, it changes the effective length (and thus resistance) in the circuit.
What does it consist of?
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It consists of a coil of resistive wire and a sliding contact (wiper).
What is the function of the switch?
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A switch is used to open or close a circuit, thereby controlling the flow of current.
What is a resistor used for?
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A resistor is used to limit current, divide voltages, and adjust signal levels.
When does the temperature of a resistor rise?
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Its temperature rises when electrical power is dissipated as heat (P = I²R).
How are resistors rated?
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They are rated by their resistance value (Ohms), power rating (Watts), and tolerance (%).
What is the difference between a fixed resistor and a variable resistor?
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A fixed resistor has a single, unchangeable resistance value. A variable resistor (like a potentiometer or rheostat) allows its resistance to be adjusted.

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