Home     Contact     Forum     Projects     Experiments     Circuits     Theory     BLOG     PIC Tutorials     Time for Science     RSS     Terms of services     Privacy policy  
   
 Home     Forum     Projects     Experiments     Circuits     Theory     BLOG     PIC Tutorials     Time for Science   

Author Topic: When use a PNP and when a NPN tramsistor?  (Read 5971 times)

0 Members and 1 Guest are viewing this topic.

FrED

  • Guest
When use a PNP and when a NPN tramsistor?
« on: March 22, 2008, 22:02:03 PM »
Hallo!
I have a question that came to me when i try to design a switch using a relay and a transistor.

I know that there are PNP and NPN transistors. What is the difference they have and why do we have 2 types of transistors? And when do we have to use a NPN and when a PNP?

Andre

  • Guest
Re: When use a PNP and when a NPN tramsistor?
« Reply #1 on: March 23, 2008, 09:21:04 AM »
As long as i know here is no "WHEN".

Basically, the difference between PNP and NON is that PNP gets a + to the collector and needs 0 to the base to become conductive.
NPN gets 0 to the collector and needs + to become conductive.

This is the main difference. So, if you need to switch for example a relay and you have an output that sends 0 when you need to turn it on, then you must use a PNP transistor.

Also, is very usefull in reversing signals (like amplifiers).

There are no more differences between them as long as i know...

FrED

  • Guest
Re: When use a PNP and when a NPN tramsistor?
« Reply #2 on: March 28, 2008, 00:11:11 AM »
so it is a matter of judgment

kam

  • Administrator
  • Hero Member
  • *****
  • Posts: 1849
Re: When use a PNP and when a NPN tramsistor?
« Reply #3 on: March 28, 2008, 00:41:57 AM »
no not exactly. Some times it is mandatory some times not to use PNP or NPN

FrED

  • Guest
Re: When use a PNP and when a NPN tramsistor?
« Reply #4 on: April 03, 2008, 23:55:13 PM »
pffffff :-[

Supernova

  • Full Member
  • ***
  • Posts: 149
Re: When use a PNP and when a NPN tramsistor?
« Reply #5 on: April 04, 2008, 18:27:25 PM »
Man, you have to understand. There is not neutral or ground or something like that in digital electronics. There is only + and - and they are handled the same

So if you have a + signal and you must use a transistor with it, you need a NPN otherwise a PNP...

FrED

  • Guest
Re: When use a PNP and when a NPN tramsistor?
« Reply #6 on: April 11, 2008, 19:08:51 PM »
I think i need to learn some more for transistors  :-\ :-\ :-\

Supernova

  • Full Member
  • ***
  • Posts: 149
Re: When use a PNP and when a NPN tramsistor?
« Reply #7 on: April 12, 2008, 13:40:33 PM »
Yep, they are very interesting...