According to some sources, diode is a bipolar device since it has both electrons and holes as carriers. However according to some other sources, diode is a unipolar device because it allows current to flow only through one particular direction? Which is correct? (There is some generalised confusion regarding classification of power semiconductor devices in categories such as majority or minority carriers and unipolar or bipolar devices.)

 

According to some sources, diode is a bipolar device since it has both electrons and holes as carriers. However according to some other sources, diode is a unipolar device because it allows current to flow only through one particular direction? Which is correct? (There is some generalised confusion regarding classification of power semiconductor devices in categories such as majority or minority carriers and unipolar or bipolar devices.)

The statement that the diode passes a current in one direction is not true. It all depends on the magnitude of the applied voltage. A special case is a zener diode.

 

According to some sources, diode is a bipolar device since it has both electrons and holes as carriers. However according to some other sources, diode is a unipolar device because it allows current to flow only through one particular direction? Which is correct? (There is some generalised confusion regarding classification of power semiconductor devices in categories such as majority or minority carriers and unipolar or bipolar devices.)

Don't worry. About it. Unipolar is a phrase you'll never hear again after finishing an elementary chapter on PN junctions. It sounds like you have a better grasp on the topic than most textbook authors. Move on.

 

The statement that the diode passes a current in one direction is not true. It all depends on the magnitude of the applied voltage. A special case is a zener diode.

But generally, when they say diode, they mean PN or Schottky diode and not the Zener diode. If its Zener diode, it is specifically mentioned as Zener diode.

 

But generally, when they say diode, they mean PN or Schottky diode and not the Zener diode. If its Zener diode, it is specifically mentioned as Zener diode.

I met in the radio amateur literature about the use of conventional diodes as zener diodes. Using them, a stabilization of 100-300 volts was obtained. But in doing so, it was necessary to find the diode experimentally for the necessary voltage.

 

Anything with 2 poles is bi-polar by definition.

 

L

Anything with 2 poles is bi-polar by definition.

so a unipolar stepper motor only has one pole?

 

Yea, the name in that context refers to the current direction. As in the motor direction can be changed without reversing the current.

So the device as a whole is unipolar, but contains bipolar components.

Yes...it's a relative term.