a quick leccy question

[geordie_racer]

hi im wanting 2 put 1 of these switches in my car but need 2 no if i need a resistor 2 stop the led blowing,

http://www.novaload.net/forums/album_view.php?id=757

if i do need a resistor wot type and rating should it b and i take it i just put it inline on the positive leg

cheers
chris

[Nova-Boy]

That is a neon light sorry and will not work in your car. It needs an alternating wave and runs off 250V. Your car is DC 12V

[Aragorn]

ummmm no

it clearly says 2.2v 25mA LED there

now

LED wants 2.2v
uve got 13.8v

u need to sink 11.6v

sooo V=IR => R=V/I
R is resistance, I is current, so...

R = 11.6/0.025

R = 464ohms

now i doubt u can get 464ohm resistor so get the closest to it which is a 470 - maplin code M470R

:D

[Nova-Boy]

Ok then the LED would work then off the 2.2v supply but the switch could not handle 1.5amps like stated for an AC wave. If 1.5amp was drawn DC it might burn the contacts out much quicker.

Looking back i did that last post at 4:05 about 10 mins befoire i finished work so i was rushing and misread the specs.

:oops:

[Aragorn]

depends what he wants to power with it

a switch rated at 1.5A at 230v AC should easily cope with 1.5A at 12v

remeber its the current that generates the heat - not the voltage

[geordie_racer]

oh i seem 2 have caused trouble here :lol: im wanting 2 use the switch 2 power a fiesta boot solenoid does this help?

[Nova-Boy]

Leave me alone! :cry: When i was saying about current last night i meant that you can use a larger AC current than DC current because the DC creates more heat cos the AC is constantly turning on and off.

But yeah that switch should be ok if you use a Resistor.

Sorry for misleading i was rushing. :oops: :roll:

[geordie_racer]

don't worry bout it we all make mistakes and we got the right answer in the end
cheers lads
chris

[Nova-Boy]

I would have thought it would be ok anyway for a boot pop as it will only be in use for a second or something wont it? How much current will it take?

Would it be a good idea to just use the switch to sitch a relay to power your solanoid? Like you do for wiring spot lights etc etc.

[geordie_racer]

never thought about that wot relay would i need 2 use. im not using the switch to pop the boot lock but 2 pop the interior handle so i just have 2 hold a button push the door and it opens. don't suppose ne1 could provide a wiring diagram and a maplin product code :D

chris

[mikeoxford]

copy the boot realease diagram on nova-land.com it uses a buzzer and a 6 pin PCB relay,

i made it so it was inoperable with ignition on - to avoid popping the boot, and a buzzer would sounds instead, turn igntion off and pop away!

[Nova-Boy]

Sounds like a good idea.... But does the boot light work with the ignition off?? I have only just got mine working (wires weren't connected) and cant remember off the top of my head. The glovebox one only works with the ignition on though!