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Re: [TCML] Transistor Questions (slightly O.T.)



Hey Christopher...

If Im reading this right... sounds like you want a PNP transistor to create the work you are trying to accomplish...

Scot D



Christopher Karr wrote:

Hello everyone,

I'm aware of the function of a transistor, though, for my purposes, an analogy must be made:

An NPN transistor is like a N.O. SPST  push-button switch (with a diode in series, of course). The pushing of the button is analogous to the insert of base-current in an NPN transistor.

That being said, is there any sort of transistor which is analogous to a N.C. SPST push-button?  Were there such a design, one could simply use a square-wave which never goes below '0V' to drive a push-pull setup.

When the signal is high, base-current would be fed to the normal NPN transistor(s), turning them on. Also, when the signal is high, base-current would be (fed to or pulled from?) the 'normally-closed' transistor, turning it off. If the on-times and off-times of these transistors were properly matched, one could use nothing but a 555 IC (and maybe a couple signal-level transistors) to drive medium- to high-power transistors in a push-pull arrangement.

If such a device has not yet been invented, I claim sole rights! ;)

Thanks,

- Christopher Karr
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