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Bumped by Community user
Bumped by Community user
Bumped by Community user
Bumped by Community user
Bumped by Community user
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edit approved Feb 18, 2016 at 4:14
Kishan Kumar
edit approved Feb 18, 2016 at 4:14
Kishan Kumar
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For example, the

enter image description here the diagram in my text book https://i.sstatic.net/IEzwR.jpg shows shows a filament lamp, in series with a uniform resistive wire, which can have its voltage and current varied by moving the sliding contact, e.g., a rotatable wheel. However, why is a potential divider able to reduce the current through the filament lamp to zero, but a variable resistor in series with the filament lamp cannot reduce current to zero, I.e., there is still a very small amount of current through the lamp when a variable reisistor is used.

For example, the diagram in my text book https://i.sstatic.net/IEzwR.jpg shows a filament lamp, in series with a uniform resistive wire, which can have its voltage and current varied by moving the sliding contact, e.g., a rotatable wheel. However, why is a potential divider able to reduce the current through the filament lamp to zero, but a variable resistor in series with the filament lamp cannot reduce current to zero, I.e., there is still a very small amount of current through the lamp when a variable reisistor is used.

For example,

enter image description here the diagram in my text book shows a filament lamp, in series with a uniform resistive wire, which can have its voltage and current varied by moving the sliding contact, e.g., a rotatable wheel. However, why is a potential divider able to reduce the current through the filament lamp to zero, but a variable resistor in series with the filament lamp cannot reduce current to zero, I.e., there is still a very small amount of current through the lamp when a variable reisistor is used.

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John
John
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How is a variable potential divider able to reduce current/voltage through a component to zero, unlike a variable resistor?

For example, the diagram in my text book https://i.sstatic.net/IEzwR.jpg shows a filament lamp, in series with a uniform resistive wire, which can have its voltage and current varied by moving the sliding contact, e.g., a rotatable wheel. However, why is a potential divider able to reduce the current through the filament lamp to zero, but a variable resistor in series with the filament lamp cannot reduce current to zero, I.e., there is still a very small amount of current through the lamp when a variable reisistor is used.