Welcome To the Hoffman Amplifiers Forum

September 06, 2025, 12:31:25 am
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Transistor Testing NPN & PNP Video  (Read 5230 times)

0 Members and 1 Guest are viewing this topic.

Offline plexi50

  • Level 4
  • *****
  • Posts: 4649
  • Tube Tone
Hoffman Amps Forum image
Transistor Testing NPN & PNP Video
« on: October 26, 2011, 06:13:57 pm »
I found this video on youtube that shows how to test your questionable transistors
I like the biasing part that determines the Collector,Base,Emitter/ What if the transistor will only bias up on one side? Is the tansistor bad?
Transistor Testing, the Basics
« Last Edit: October 26, 2011, 06:47:50 pm by plexi50 »

Offline stingray_65

  • SMG
  • Level 3
  • *****
  • Posts: 926
Hoffman Amps Forum image
Re: Transistor Testing NPN & PNP Video
« Reply #1 on: October 26, 2011, 11:12:46 pm »
OK<

From what I get from watching the vid is this.

It does not determine if the transistor is good or bad.

It does show how to identify PNP or NPN and which lead is B base

Then we learn by biasing which lead is C collector

By default the  last lead is E emitter.

SO by "biasing" we put a resistor between the C and B and not E and B so it does only bias on 1 side.

At least that's my take on it.

I never trusted anything I couldn't solder with a big Weller soldering gun any how :laugh: so take what I think with a grain of salt!

ray

My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention (H. Lamarr)

Offline PRR

  • Level 5
  • *******
  • Posts: 17082
  • Maine USA
Hoffman Amps Forum image
Re: Transistor Testing NPN & PNP Video
« Reply #2 on: October 26, 2011, 11:50:51 pm »
Notice it is an analog needle-meter, NOT a DMM.

It also has 1.5V internal battery for Ohms.

Yes, it will sort _DEAD_ transistors. On this type ohm-meter, a happy junction will show infinity one way and half-scale the other way, on all ranges. Sick junctions show dead-short. Sick junctions with huge power available will be found blown-Open.

Such technique can not tell E from C (but on TO220, TO3, TO5 you already know the tab/case is C). You need to test for current gain or junction breakdown to tell E from C.

 


Choose a link from the
Hoffman Amplifiers parts catalog
Mobile Device
Catalog Link
Yard Sale
Discontinued
Misc. Hardware
What's New Board Building
 Parts
Amp trim
Handles
Lamps
Diodes
Hoffman Turret
 Boards
Channel
Switching
Resistors Fender Eyelet
 Boards
Screws/Nuts
Washers
Jacks/Plugs
Connectors
Misc Eyelet
Boards
Tools
Capacitors Custom Boards
Tubes
Valves
Pots
Knobs
Fuses/Cords Chassis
Tube
Sockets
Switches Wire
Cable


Handy Links
Tube Amp Library
Tube Amp
Schematics library
Design a custom Eyelet or
Turret Board
DIY Layout Creator
File analyzer program
DIY Layout Creator
File library
Transformer Wiring
Diagrams
Hoffmanamps
Facebook page
Hoffman Amplifiers
Discount Program