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Variable resistors.

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Some circuits require a variable resistance rather than a fixed one.

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This could be to adjust the current in the circuit or to detect changes in light or temperature.

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In these cases, we use

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Variable resistors or potentiometers.

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The maximum value of the component will be indicated on it.

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For example, 1 Kiloohms, 10 Kiloohms, 100 Kiloohms, etc.

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The higher is the resistance, the lower is the intensity.

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Light-controlled variable resistors or LDR, light-dependent resistors.

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When we increase the intensity of the light that shines on it, the resistance value decreases, i.e. the more light there is, the less resistance we have.

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This way, it can detect changes in light and stop the flow of the current in darkness.

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Temperature-controlled variable resistors or thermistors, thermally sensitive resistors.

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These can be NTC, negative temperature coefficient, or PTC, positive temperature coefficient, depending on whether their resistance decreases or increases as the temperature rises.

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Thank you for watching.