| zilog |
I have wired a NPN BJT in the manner shown in this schematic 
with the result that it is internally open.. I need to sometimes have the emitter a few volts higher than the base, do I need a diode in series with the emitter, or have I experienced something weird? |
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| Juergen Knoop |
a diode would help, otherwise you would have to limit the breakdown current to a few mA.
I don't know what is considered a safe current.
regards |
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| ilimzn |
Base-emitter reverse break down voltage is on the order of 8V, which means you ran an 8V zener from a 15V source with no current limit - in other words, you killed it.
If you need the B-E junction reverse biassed, you will need some form of protection, either a series diode or a parallel diode, depending on the particular case. |
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| zilog |
Thanks,
I had completely overlooked that parameter. |
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| Mooly |
Hi,
Running as shown in post 1 (current limited) will generate a lot of "white noise" across the junction. This was the classic white noise generator 30 years or so ago.
Regards Karl |
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