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Max VBE voltage of BJT transistor?

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eem2am

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Max VBE voltage of BJT?

hello,

this BJT has a maximum Vbe of 9V.

http://www.fairchildsemi.com/ds/KS/KSE13003.pdf

But can it support more than 9V just so long as there is no current flowing through the BE junction?

(eg say if emitter was connected to a diode's anode, the cathode of which is connected to a +16V rail............and the base is connected to ground)
 

Kral

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Re: Max VBE voltage of BJT?

eem2am,
This configuration is safe, although no manufacturer would guarantee it, since the base-emitter current is limited to the leakage current of the diode, which would be much less than the Ibeo rating of the base-emitter junction. The actual voltage across the eb junction is indeterminate in this case.
Regards,
Kral
 

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Max VBE voltage of BJT?

The max allowed voltage for the reverse-biased emitter base junction is 9V where the transistor is turned off.

You have the emitter at about +15.3V and the base at ground which is a reverse bias of 15.3V so the emitter-base diode will have avalanche breakdown and conduct a lot of current. The current slowly eats away the base-emitter junction and reduces the beta of the transistor.
 

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