On Wed, 24 Apr 2013 20:36:32 +0100, bm wrote:


"Major Scott" wrote in message
news
On Wed, 24 Apr 2013 08:33:48 +0100,
wrote:

Major Scott wrote:
On Tue, 23 Apr 2013 16:58:35 +0100, Dave Plowman
wrote:

In article ,
Major Scott wrote:




LEDs are current, not voltage, driven.

When there's a series resistor, then you can think of them as voltage
driven. Anyway electronics to lower the current can be made without
pulsing.

No, the series resistor merely determines the maximum current that could
flow through the LED.

Take for example a 6 volt DC supply connected to an LED in series with a
200 ohm resistor.
2V 20mA at the LED, 4V 20mA in the resistor.

Now change the supply to 4V.
2V 10mA at the LED, 2V 10mA in the resistor.

**** a duck, they DID teach you something.

I have a ****ing degree in it (not that it gets you a job).

--
Basketball analyst: "He dribbles a lot and the opposition doesn't like it. In fact you can see it all over their faces."