Andrew Warren wrote:
>
> Tjaart van der Walt <tjaart@wasp.co.za> wrote:
>
> > Something you could consider, is to hook a bicolour (two terminal)
> > LED to the output of a common inverter gate, and a voltage divider.
> > By driving the input high, low, or toggling, you can create a couple
> > of colours. Power the inverter from 10V.
>
> Tjaart:
>
> If I correctly understand what you're describing, that method works
> even WITHOUT the inverter... A 2.5-volt drop across the LED is
> enough to light it, so you can just put the bicolor LED between the
> PIC and the voltage divider.

The bicolour (bicolor in America) LED drops about 2.2 volt, so with
the output at Vdd - 0.7 volt (as per specs), you'll find the one LED
quite faint. When driving both by toggling them, you'll find a quite
unsatisfactory result. (I discovered this the hard way)

I'm not sure why the bicolours need more juice, but they do.

You also have to keep in mind that you have to drive the LED hard enough
so you won't see the difference between 100% duty cycle and 50% duty
cycle.

--
Friendly Regards

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