Diode symbol polarity (PN junction): The arrow/point in the schematic depiction of a diode points toward which semiconductor region and terminal name?

Difficulty: Easy

Correct Answer: the n-type material, which is called the cathode

Explanation:


Introduction / Context:
Correctly identifying diode terminals from the schematic is critical when orienting the device on a PCB. The cathode end must align with the symbol's bar to guarantee forward conduction in the intended direction and proper rectifier behavior.


Given Data / Assumptions:

  • Anode corresponds to p-type; cathode corresponds to n-type.
  • Conventional current flows from anode to cathode when forward-biased.
  • Markings: the cathode lead is often marked with a painted stripe on axial diodes.


Concept / Approach:
The conventional diode symbol shows a triangle/arrow-like point directed toward a vertical bar. The bar denotes the cathode (n-type side). Thus, the pointed tip indicates the direction toward the cathode. Remember ”point to bar = cathode,” and ”current flows from anode (no bar) to cathode (bar)” when forward-biased.


Step-by-Step Solution:

Find the bar in the symbol; it represents the cathode.Note the pointed side faces the bar; therefore it faces the cathode.Relate material types: the cathode is the n-type region, so the point faces n-type.


Verification / Alternative check:
Use a DMM diode test: positive probe to anode and negative to cathode yields a forward drop reading (for silicon, about 0.6–0.7 V). Reversing the probes yields open circuit, matching the symbol orientation rule.


Why Other Options Are Wrong:

  • Anode/p-type answers: Opposite terminal; the point does not face p-type.
  • Calling the n-type region the anode (Option A) is incorrect terminology.


Common Pitfalls:
Mixing up electron flow with conventional current or confusing LED light arrows (which depict emitted light) with the diode polarity indicator.


Final Answer:
the n-type material, which is called the cathode

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