Re: Triac question

["Stuart Meier" <stuartm2007@xxxxxxxxx>]

Thanks Nick, but I think that as shown it will work when BOTH left and
right
are on, but not when EITHER (ie OR!) the left lamp, or the right
lamp...hence two relays (or other devices)

Stuart
----- Original Message -----
From: "Nick Austin" <nick.w.austin@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Monday, September 24, 2007 11:44 AM
Subject: Re: [ukha_d] Triac question


On 9/24/07, Stuart Meier <stuartm2007@xxxxxxx> wrote:
>
> I'm hoping an electronics whizz can help me...
>
> I need several "blocking diodes" for 240ac, but of course
strictly that
> doesn't exist. In essence, the job is to turn a light on in the middle
of
a
> corridor if the light at either end is on, but without the opposing
end
> coming on too, ends being independently switched. I could use some
blocking
> relays, but that would be £8 each, and significant space. OK, I
could make
a
> small board for a PCB mounted one but is there a better option...
>
> Can I use some of the triac's I have knocking about, by wiring the
gate to

> the input, perhaps via resistor. Resistor value?

If there is no other control of the middle lamp then you only need one
relay.  I tried to do it as ASCII art but failed so here a diagram:
http://xs.to/xs.php?h=xs319&d=07391&f=lamp_switch.jpg

Nick.


[Non-text portions of this message have been removed]