Hi,

I have discovered the fatal flaw in my pull switch and humidistat bathroom
fan.

I cannot tell if the humidiatat is on or the pull switch is on.

I have worked out the wiring (which is how I first proved that the
humidistat was on most of the time) but I would like to fit a small LED
which only lights when current is passing through the switch.

To do this I need a 240v LED which can be mounted in a small hole in a
plastic casing.

Looked in Maplins but can't find a 240v LED - although most don't seem to
have a voltage rating.

Any ideas/sources?

TIA
Dave R

--

Looked in Maplins but can't find a 240v LED - although most don't seem to
have a voltage rating.

Any ideas/sources?

Try looking for Neon rather than LED

Sean

"Sean Delere" wrote in message
...
Looked in Maplins but can't find a 240v LED - although most don't seem
to
have a voltage rating.

Any ideas/sources?

Try looking for Neon rather than LED

Sean



Thanks guys - will do

In article , David W.E.
Roberts writes
Hi,

I have discovered the fatal flaw in my pull switch and humidistat bathroom
fan.

I cannot tell if the humidiatat is on or the pull switch is on.

I have worked out the wiring (which is how I first proved that the
humidistat was on most of the time) but I would like to fit a small LED
which only lights when current is passing through the switch.

To do this I need a 240v LED which can be mounted in a small hole in a
plastic casing.

Looked in Maplins but can't find a 240v LED - although most don't seem to
have a voltage rating.

Any ideas/sources?

use a neon, not an LED. You can wire up LEDs to work at 240V but it
would be far simpler to use a mains neon, which would give a very
similar effect.
--
Tim Mitchell

In article ,
David W.E. Roberts wrote:
Looked in Maplins but can't find a 240v LED - although most don't seem to
have a voltage rating.

That's because an LED is a DC current operated device. For normal DC
operation they require a series resistor the value of which depends on the
voltage it's running off and the current you wish to drive it with. For AC
use, you require a diode as well.

It's more normal to use a neon indicator, but if you'd prefer the look of
an LED it's easy enough if you can solder.

I *think* RS components do mains LED indicators ready made - they
certainly exist, I've got some.

--
*Change is inevitable, except from a vending machine.

Dave Plowman London SW 12
RIP Acorn

I have worked out the wiring (which is how I first proved that the
humidistat was on most of the time) but I would like to fit a small LED
which only lights when current is passing through the switch.


Did you get your answer yet, David W.E.?

I read most of the thread but couldn't see any simple answer...

As far as I am concerned, you need to look at the *current* flowing
through the switch (or the humidistat), as I guess they are connected
in parallel...

I saw a circuit using a LED and a few diodes, which in effect will
monitor the current. It was used as an indicator for a normal (no
neutral) 240V light switch.

Quote: (for 'Lamp' read 'Motor')

fixed width font
LED
----RES180R---||----
| |
SWITCHED-FEED----||--||--||--||------LAMP
| |
---------||---------

--||-- = DIODE

A bit heavy on component count but lights evenly independent of lamp
load, choose diodes to match full lamp current. LED is low current
(5mA).

All parts are live, including the LED. For safety don't poke the led
thro the panel, use a plastic holder.

Extra components would be required to meet BS/VDE safety.

Unquote... (from uk.diy - "Power an LED from a light switch?")

"Abdullah Eyles" wrote in message
om...
I have worked out the wiring (which is how I first proved that the
humidistat was on most of the time) but I would like to fit a small LED
which only lights when current is passing through the switch.


Did you get your answer yet, David W.E.?

I read most of the thread but couldn't see any simple answer...

Main answer I got was that I asked the wrong question.

The lights in switches are apparently neons not LEDs.