On Sep 6, 12:25*am, Phil Addison wrote:
On Sat, 05 Sep 2009 23:59:22 +0100, "Dave Plowman (News)"

wrote:
In article
,
* *NT wrote:
The LED would need a rectifier of course.

You just parallel a reverse connected diode to the LED for AC. Plus a
suitable current limiting resistor, of course.

That's neat. That will bypasses the LED on the reverse cycle, and is
probably easier to wire in than a series diode. It allows you to use a
tiny low voltage diode whereas the series one needs to be a bigger mains
rated 1N400x series. OTOH it draws twice the current of the series
solution, but still a mA or so.

Doesn't the 1/2 wave rectification halve the brightness though? An
electrolytic capacitor in parallel should solve that if it doesn't need
too many uF's - haven't calculated the size.

Phil

Thats another downside of the circuit, you cant smooth the power with
a little reservoir capacitor.


NT