Semiconductor P-N Junctions: Transistors or Diodes?

[cscott]

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?

 

[Danger]

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.

 

[Gokul43201]

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.

 

[cscott]

Oh, ok. Thanks!

 

[Danger]

Thanks for the clarification on the triode, Gokul. I always thought that it was just anything with 3 leads.

 

[Gokul43201]

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.

 

[Danger]

I've never worked with any electronics. As my post should tell you, I know almost nothing about it. 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).