I thought i had this transistor ordeal sorted...
Now then? The data sheet ..
Emitter base 4v
Collector base 50v
Collector emitter 50v
How can you use 12v regulated as pass transistor (via the zener) but the base has a max of 6v...
Huh?
I thought i had this transistor ordeal sorted...
Now then? The data sheet ..
Emitter base 4v
Collector base 50v
Collector emitter 50v
How can you use 12v regulated as pass transistor (via the zener) but the base has a max of 6v...
Huh?
VBE vs. VEB
What's in a name? A lot.
Are you saying up to 50v can be applied to the base?.. 8)
Give them an inch and they'll take a mile.
There's that VCBO spec, too
Runaway, are you sober?
cjdelphi:
Are you saying up to 50v can be applied to the base?.. 8)
I just could not let this rest.
I don't have one of those 2SC jobs, but I have a 2N3904 (lots of 'em). The 3904's VCBO spec is 60V.
I left 50V in the dust, I applied 73V to the Base.
The difference between VB and VC is 24V
1/4W on the little darling, too, but still.
Not much more to do with this circuit but to prove a point.
I can upload a video of the experiment if necessary.
[Coming Up... Panic in the streets]
cjdelphi, it is all about relative voltage, and direction. VEB is the same as saying -VBE
The maximum that should be applied to the base with respect to the emitter is -4V. So if you connect your DMM black lead to the emitter and the red lead to the base, it should never go below -4V.
I was merely confirming what I thought was true, that diagram and voltage is what I expected would happen, I've always stuck with 6v or less with the base pin.. you had no point to prove as I was not claiming anything to begin with?....
cjdelphi, there may be some hostility because you are a bit of a jerk when people disagree with you.
polymorph:
cjdelphi, there may be some hostility because you are a bit of a jerk when people disagree with you.
I'm a jerk to anyone who's being a jerk, i may not understand it, but my questions arise from not totally understanding it, and when others are happy with it /just does/ and does not question it at all, that leads to ignorance, if i'm going to use it, then i want to know how to fully use it.
Vague answers like 'it does' is not an answer...
As for this question, why the hostility? i'm not even disagreeing with anyone here let alone attempting to argue, so why the hostility, maybe it's it's just them.....
if anyone thought i was claiming "transistors can only handle up to 6v' no wrong, i've used 12v myself plenty of times, I did not realize that the 6v figure was for "reverse" and i'm still not entirely sure ..
so if i apply -7v to the base of the transistor it will begin to conduct at the breakdown voltage?.
or are you saying..
apply 7 on the emitter? and it will begin to conduct from the collector to emitter?..
this is what i mean by vague for me.....
I've seen and experienced you being a jerk when you -perceive- others being a jerk, but not necessarily are.
Anyway, your question was answered with the first answer. Now we're just muddying the waters.
cjdelphi:
so if i apply -7v to the base of the transistor it will begin to conduct at the breakdown voltage?.
That would be the size of it.
In some configuration - I think that might be it or is it biasing collector and emitter backwards with base open (which by definition has the same effect) - this apparently functions as an excellent noise diode.
Although nominally N-P-N a transistor is not at all symmetrical - the emitter is usually
very strongly doped n-type to reduce its internal resistance and increase the number
of charge carriers it can inject into the base. This makes the emitter-base junction
have a very low reverse-breakdown voltage (I believe rather similar to a zener junction,
very narrow depletion zone).
Conversely the base-collector junction is lightly doped and optimised for large
reverse-breakdown voltage as this is the normal state for it.
cjdelphi:
if anyone thought i was claiming "transistors can only handle up to 6v' no wrong, i've used 12v myself plenty of times, I did not realize that the 6v figure was for "reverse" and i'm still not entirely sure ..so if i apply -7v to the base of the transistor it will begin to conduct at the breakdown voltage?.
Yes and if not current limited by external resistor will destroy the transistor.
or are you saying..apply 7 on the emitter? and it will begin to conduct from the collector to emitter?..
Applying > +5vdc between base/emitter will also destroy most NPN transistors because of excessive current flow unless also limited by external resistor in the base circuit. When positive voltage is applied to the base in excess of the forward voltage drop rating of the base/emitter junction, current will flow but the voltage drop across the B/E junction will remain constant at the Vf rating of the B/E junction, until it melts open. Just like when powering a simple led, current control is what matters. An npn transistor is a current amplifying device, not a voltage controlled device.
this is what i mean by vague for me.....
The base-emitter junction in breakdown does make a nice noise source. Of course, a zener diode makes a good white noise source, too, which is why they need to be so effectively bypassed.