Brian Jones wrote:

> Tjaart,
>             for those of us without an electronics background (OK so
> you might ask what on earth are we doing on PICLIST -in my case the
> answer is 'Learning!') would you live to explain further the naming
> of Vdd, Vcc etc.

Sorry.

In TTL (transistor-transistor logic) chips, the technology is based on
bipolar transistors. Since you connect the Collector of a NPN transistor
to the positive side, and the Emittor to the negative side, the chips are
marked with Vdd for positive, and Vee for negative (ground)

In CMOS (complementary metal oxide silicon) chips, the technology is
based on field-effect transistors. You connect the Drain to the positive
side, and the Source to the negative side, hence Vdd and Vss.

You can use this nomenclature to know if a chip is based on bipolar, or
FET technology. (Fet being MOS, GaAs etc)

I figured this out myself, so I could be completely and utterly wrong,
in which case I'll deny having ever said this <GRIN>

<PLUG MODE>
BTW, have you voted on my page ?
</PLUG MODE>

--
Friendly Regards

Tjaart van der Walt
mailto:tjaart@wasp.co.za

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