The only diode check type conduction in a bipolar transistor should be between the base and emitter. What exactly is a BC548B? If you want leakage checks you need something you can plug all three leads into like my Sencore Cricket.
Nip down to Maplin and get a meter with a transistor tester.
While a normal meter can test go or no go it cant test HFE problems.
--- Sure it can. (View in Courier):
Starting with the pot cranked to maximum resistance, rotate it so that some convenient current (Ic) is displayed by the ammeter then, without disturbing the setting of the pot, disconnect the meter from the collector, place it in series with the base, and connect the collector to +V:
+V>-+-----+-------+ | | | [1M]--------------+The meter will now be indicating the base current (Ib) and all that's left to do is to calculate Hfe:
Ic Hfe = ---- Ib
and, from the transistor's data sheet, to determine whether the transistor is in spec or not.
-- JF
That's fine and dandy but the OP didn't even know what symbol represented a diode check on his vom. And this has been a teaching thread for him. I know you have a need to right wrongs, just keep it out of this thread so it doesn't turn into the usual argument.
-- That\'s not true. Matter of fact, the way to determine which lead is the base of a transistor with an unknown pinout is to find the lead which diode-conducts to the other two leads.
-- Geez, Plowie, everything was going along fine until you decided to open up that big fucking mouth of yours and criticize what didn\'t need criticizing. I guess (according to you) that I should have started another thread and referenced it to this one just to keep from offending your delicate sensibilities about what\'s allowed in the thread, ya fuckin\' Nazi.
-- Any number of things. What did you do to obtain those readings? That is, what was connected to what when you got the various readings?
As if by magic, you've proven my point.
bye
plonk
-- You made no point, and seeing that there was no rancor on my part before you started your unwarranted criticism, I\'d say what was proven was that you\'re a loudmouthed troublemaker.
And you are ?
How many posts in s.e.b does it take to explain how to test a transistor ?
Graham
--- Generally a truly helpful poster.
However, when it comes to dealing with snotty-assed shit like you I have no compunctions at all about slapping you around and treating you the way you treat other people.
---
--- As many as it takes until the OP gets it. I notice your sorry ass hasn't stepped up to the plate to help, instead all you want to do is try to pick a fight. Stupid ass.
-- JF
John is screaming into my kill filter, wonderful :)
Took four posts just to show the OP that his meter had a diode check function.
-- Hardly screaming, but it got through, didn\'t it?
This is not true, as can be easily verified by experiment.
the B.
educated
make
meter
conduct
Not if he is using his analogue (moving coil) meter. In this case the BLACK lead will be putting out +ve and when placed on the base of the NPN transistor it will bias each diode ON when the RED lead is on either of the other 2 terminals (assuming the transistor is ok).
Ok dammit :) Now I have to go dig up a transistor because this is not how I remember it.
-- #1 Offishul Ruiner of Usenet, March 2007 #1 Usenet Asshole, March 2007 #1 Bartlo Pset, March 13-24 2007 #10 Most hated Usenetizen of all time #8 AUK Hate Machine Cog Pierre Salinger Memorial Hook, Line & Sinker, June 2004 COOSN-266-06-25794
--
Not true.
An NPN looks like this: (View in Courier)
+-->|--C
|
B--+
|
+-->|--C
and a PNP like this:
+--|Have fun.
>
>
>Not if he is using his analogue (moving coil) meter. In this case the
>BLACK lead will be putting out +ve
...
-- Oops... Page 21.
In message , Meat Plow writes
That is correct with *most* analogue meters but I have had high impedance (FET buffered) analogue meters that don't behave that way.
-- Clint Sharp
The difference is in the meter. Digital meters put the plus on the red lead for ohms - analog meters put the plus on the black lead, so that the resulting current flows the same way through the meter movement. Digital meters don't need to do that - they do the polarity conversion in software. :-)
Hope this helps! Rich
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