Advanced Qualification · A-002 Advanced components and circuits · A-002-005-005

The silicon controlled rectifier (SCR) is what type of device?

1. A NPPN
2. B PNNP
3. C PPNN
4. D PNPN

Correct answer: D — PNPN. From the official ISED question bank, verified word for word.

Why

A silicon controlled rectifier, or SCR, is built from four layers of semiconductor material arranged in an alternating pattern of positive and negative types, specifically starting with a positive layer, then negative, then positive, and finally negative again. The full explanation — and one for every question — is in Pro.

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Advanced components and circuits: semiconductors, amplifier classes, oscillators, mixers, filters and digital logic.

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