I am using a couple of AND gates to turn on transistors. The datasheetssay it can output a max of -24mA at HIGH. I am attaching the output toa 1K resistor - then to- the base of a NPN transistor. Does thepotential amperage need to be positive in order to turn on(saturate)the transistor?

I think you are getting confused by datasheets. When it says '-24mA'for Ioh (for which there will be a Voh specified, incidentally) itmeans the current is going into the device (from an electron flowperspective).Look at the current - from an electron flow view, the current willenter the emitter, move through the base and go through the outputstage of the gate to the positive power supply.So assuming you are running your logic from +5V, then it will operate aNPN just fine, and a 1k base resistor should be fine as well.CheersPeteS

fluffy EeyoreI'll give you a Q/C report !Graham

Can base amperage on an NPN be negative, and still work?

Sep 03, 2006 84 Replies

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Eeyore 19 years ago

fluffy Eeyore

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I'll give you a Q/C report !

Graham

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Winfield Hill 19 years ago

I especially liked "Can be applied for the handy type set operational amplifier of general purpose in application of low voltage single supply type which is properly biased of the low voltage source."

Thanks, - Win

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redbelly 19 years ago

Exactly. We don't say "amperage" simply because it is our custom to say current instead. Trying to rationalize or impose consistancy in language will often get you into trouble.

Mark

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Eeyore 19 years ago

Yes quite.

Without the noseless typo it gets off to a slow start these days !

Graham

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Iwo Mergler 19 years ago

My tastebuds have evolved to maximize calories. :^)

Iwo

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