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Semiconductor diode, Meaning (SPM Physics)

A component made from a p-n junction that allows current to flow in one direction only.

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EnglishSemiconductor diode
Bahasa MelayuDiod semikonduktor
中文半导体二极管

Definition

A component made from a p-n junction that allows current to flow in one direction only.

Electronics

In exam terms

A semiconductor diode is a component made from a p-n junction that allows current to flow in one direction only. When it is forward biased (p-side to positive terminal), it conducts; when reverse biased, it blocks the current.

Its circuit symbol is a triangle pointing towards a bar, and the arrow shows the direction of conventional current flow.

Example of correct use: a semiconductor diode is connected in forward bias so that current flows through the lamp, but it stops the current if the supply is reversed.

Do not confuse it with…

Do not confuse a semiconductor diode with a resistor. A resistor conducts equally in both directions and obeys Ohm's law, while a diode conducts in only one direction and has a non-linear I–V characteristic with a small turn-on voltage.

In Paper 2 you may be asked to state the function of a diode or to explain forward and reverse bias; make clear that current passes only when the diode is forward biased.

Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)

Frequently asked questions

What is the main function of a semiconductor diode?
It allows current to flow in one direction only, blocking current in the reverse direction.
When does a diode conduct?
When it is forward biased, with its p-side connected to the positive terminal of the supply.
How is a diode different from a resistor?
A resistor conducts equally in both directions, but a diode conducts in only one direction and has a non-linear I–V characteristic.

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