Need help with simple LED

[Sulla]

I need to wire up a VERY simple LED rig. I need a red LED to light up when a button is held down, and shut off when the button is let go of. The smaller the battery the better, too.

What red LED, battery, and transistor/resistor/what ever should I use? Can I get the ones I need at Radio Shack? I need something easy to get a hold of.

I assume the real wirring diagram for what I am trying to do will look something like this (simplified of course, I am no electrical engineer at all):

 

[SiR-ROUND]

Actually the resistor normally connects to the - but it doesn't really matter.

A normal red LED doesn't need much voltage or current.

The only real thing that can go wrong is fixable anyway, reverse the + and - on the LED. or kathode and anode.

You do need the resistor to keep the led from drawing too much current.

But heck, why am I xplaining all this while Google is everybodies friend?

http://www.theledlight.com/ledcircuits.html

 

[Sulla]

Awesome. Thanks. I used to have something lke that book marked but lost it somehow.

 

[Coz]

An invaluable site, that's easy to use:

http://led.linear1.org/led.wiz

Mainly for multiple LED setups, but should give ya good info.

You'd want a circuit something like this:

C.

 

[Raffles]

Those are some handy sites.

How about starting a thread or section for technical help sites/ plans?

 

[ShackMan]

<div class='quotetop'>QUOTE(raffles @ Apr 4 2007, 02:57 PM) [snapback]1455339[/snapback]</div>

Those are some handy sites.

How about starting a thread or section for technical help sites/ plans?
[/b]

The circuits posted will work easily enough. Only thing I'd like to note is that someone mentioned normally putting the resistor on the negative side; in my experience, it's best to put it on the positive. For this circuit, it won't matter a bit. But if you get into building more complex circuits, having components between ground and other connected parts will lead to uncommon grounds (where the ground potential for one part may be different than that of another part). Just an FYI ... again, for what you're trying to do, it doesn't matter.

ATM
ShackMan

 

[GeneralMayhem]

<div class='quotetop'>QUOTE(raffles @ Apr 4 2007, 02:57 PM) [snapback]1455339[/snapback]</div>

Those are some handy sites.

How about starting a thread or section for technical help sites/ plans?
[/b]

I agree. This kind of topic comes up so often, we should have a section devoted totally to electronics for props/costumes/models.


~ GM

 

[Mr.Engineer]

Well, I am currently doing that for other Forums too but you can visit my website for a bit of info. However, its still a work in progress due to my hectic work schedule and my two daughters. However, in the next three months (if I am lucky) I will do a bit about lighting up the Polar Lights Enterprise NX-01 and(or/maybe not) Enterprise NCC-1701A too.

http://chowfookcheong.com/Electronics/Lighting.htm

 

[WookieeGunner]

http://www.highlandcitadel.com/sith/LightingClass.pdf

For the switch, get a Normally Open Momentary Contact Switch.

If you go with Radio Shack, you will probably have to go with AAA batteries, though if you don't mind web order, you have options. For example Mouser (haven't used them but have heard good things) has 12mmx2.0mm batteries

http://www.mouser.com/search/ProductDetail...alkey614-CR1220

Here is a battery holder:

http://www.mouser.com/search/ProductDetail...tualkey122-2312

While I'm at it Red LED (I tried to pick a bright one):

http://www.mouser.com/search/ProductDetail...-WP7676CSEC%2fH

Resistor (50 Ohm):
http://www.mouser.com/search/ProductDetail...lkey271-49.9-RC

Switch (This switch does both Normally Open and Normally Closed, read the data sheet for the correct pins):
http://www.mouser.com/search/ProductDetail...107-DPS-11-1-EV

Of course I don't know you project, so these are all guesstimations, you're mileage may vary, not responsible for any damage, etc., etc., et cetera.