At 04:47 AM 8/26/2008, you wrote:
> >I'm just wondering though what would be the "professional" way of
> >doing this? Would you leave the LED loose and use an ammeter, or
> >would you solder it in and use a volt meter?
>
>Well, as you are strobing them, the 'super professional' way would be to
>look at the resistor voltage with an oscilloscope to see what the voltage
>drop was while the current is flowing, rather than the average that the
>meter would see. This peak value is the value you are really interested in.

Maybe. The average is a better indication of what the brightness will be.
The peak is useful for seeing if the circuit is doing what it was designed
to do.

If it's an RMS-reading meter you'll get a number that's not particularly
useful except for calculating resistor heating.


>An alternate that would work is to use a digital meter that has 'peak
>capture' facility, i.e. it will remember the peak value that it detects and
>display that value. This would give the same voltage reading as the scope. A
>meter such as a Fluke 187 or 189 has this facility.

An oscilloscope is very useful-- it can save hours of guessing. For example,
if the pulse width or rep rate is different from what is expected, the
meter will only help you guess. The 'scope will instantly show you 
exactly what
is happening (though perhaps to only a couple of decimal places rather than
3, 4, 5, 6 or even 8 places.


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