Semiconductor P-N Junctions: Transistors or Diodes?

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Discussion Overview

The discussion centers on the classification of semiconductor devices, specifically whether a semiconductor with a p-n junction is considered a transistor or just a diode. It also touches on the characteristics of transistors, particularly in relation to triodes and their functionality.

Discussion Character

  • Debate/contested

Main Points Raised

  • Some participants assert that a semiconductor with a p-n junction is a diode, noting its directional conductivity.
  • Others propose that a transistor must have at least three terminals and that it functions by controlling current through the application of a voltage at one terminal.
  • A participant clarifies that a triode is a vacuum device and not a solid-state device, contrasting it with transistors.
  • There is a mention of the misconception that any device with three leads is a triode.
  • One participant shares personal experiences with tube amplifiers, suggesting a preference for triodes among audiophiles for their sound quality.
  • Another participant expresses a lack of knowledge in electronics, sharing a nostalgic reference to changing tubes in older televisions.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether a p-n junction is classified as a transistor or a diode, and there are competing views regarding the definitions and characteristics of triodes and transistors.

Contextual Notes

Some statements rely on specific definitions of terms like "transistor" and "triode," which may vary. The discussion includes personal anecdotes that may not directly relate to the technical definitions being debated.

Who May Find This Useful

Individuals interested in semiconductor technology, electronics, and the distinctions between different types of electronic components may find this discussion relevant.

cscott
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Is a semiconductor with a p-n junction considered a transistor or just a diode? If it is just a diode, are transistors always triodes?
 
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Not my area, but... as far as I know a transistor has to be at least a triode because you need to input the control voltage.
 
cscott said:
Is a semiconductor with a p-n junction considered a transistor or just a diode?
It is a diode, not a transistor. It has greater conductivity in one direction than the other.
If it is just a diode, are transistors always triodes?
A triode is a vacuum device that works essentially like a transistor. It is not a solid state device.

A transistor must have three terminals. The idea is that by applying a (gate) voltage at one of the terminals, you can control the current flowing between the other two. The BJT is constructed essentially by sticking a pair of p-n junctions together, making sure the middle layer (the base) is really thin.
 
Oh, ok. Thanks!
 
Thanks for the clarification on the triode, Gokul. I always thought that it was just anything with 3 leads.
 
Danger said:
Thanks for the clarification on the triode, Gokul. I always thought that it was just anything with 3 leads.
Ever worked with tube-amps ? People still like to build their amplifiers out of triodes for better sound quality.
 
I've never worked with any electronics. As my post should tell you, I know almost nothing about it. :redface: The closest that I got was changing burned-out tubes in my TV (yes, I'm that old ). I've heard very often that audiophiles pay big bucks for tube amps because they provide a 'warmer' sound. I guess the closest analogy that I can think of is that of a very good painting (tubes) as opposed to a photo (solid-state).
 

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