Hey guys,
I am gathering parts for setting up an electric fan and I want to mount an LED in my dish or pillar pod to indicate to me when the fan is running. I am not very knowledgeable when it comes to complicated electronic components, but I have been searching for LEDs that will handle 12 (14) volts and aren't too bright. Can anyone here tell me where I can get these? If not, is there anyone who can tell me who to choose the right resistor to reduce the voltage down to that which I can find LEDs for?
Thanks!

 

Radio shack sells them.

John

 

Thanks John. I looked at radio shack online and didn't find much but I will go to my local radio shack store and see if they have them.
Thanks again,
Nathan

 

If you want to use the LEDs you can find at Radios shack, you can just put a resistor inline with the LED, and use different voltage level LEDs, without buring them out.

Signaldynamics.com offers them with the microstar sets. Same thing as buying the parts at Radio Shack, so you would be good to go with the parts you can get locally.
http://www.signaldynamics.com/produc...star/micro.asp

They have the install instructions on the web site :
http://www.signaldynamics.com/produc...croinstall.asp

The resistor they use use in this example is a 330 ohm resistor, which is used for voltage drop over the circuit.
Reisitance calculator :
http://www.electrician.com/resist_calc/resist_calc.htm

Good luck.

 

Thanks SSCULLY!
That is a great link! It doesn't get any easier than that. I will probably order some of those. You wouldn't by chance have any links to good sources for rocker switches or any other automotive electrical parts that are hard to find or at good prices would you?
Thanks again,
Nathan

 

Nathan,

Glad tha tis what you were looking for.

As for switches, depends on how you want them to look.

I have I think a Pilot illuminated rocker switch for my manual run on my Electric Fans, it is a surface mount switch, that mounts in a round hole, and is an incadesent bulb ( so I can switch ground to the VSC for the fans ), and have the indicator lamp work.

For my dad's electric fan kit, I used the Carling switches, which are cut outs for mounting, and larger switches ( also cost more ).
You can get a version of this at BoatsUSA, if you have one of those around.

If the local auto parts store ( AutoZone, PepBoys, Napa ) does not have what you need there are a few, but I use Wire connection for the odd stuff :
http://www.wireconnections.com/Merchant2/merchant.mv

Some of the stuff there is a bit high, but they have it in stock, and can get it out quick.

Sorry I don't have any one place, if you have an idea of what you are looking for, SPST, SPDT, illuminated ( incadesent or LED ) that might help, as I get stuff from a lot of different sites if I can't find it local.

Thanks

Steve

 

Thanks Steve,
That is a good source. I asked about other links because I have another project that I am working on. I want to build a small switch panel to put in the extra space left after replacing the oem radio with aftermarket. The switches would need to be fairly small and rectangular. I would like to find illuminated rocker switches. I realize that being so small, the may all have to work with relays. I want to put my manual fan switch, a switch to control the a/c compressor, and possibly 2 or 3 others in it. I have found a few switches on manufacturer or wholesale *I'd have to buy 250) sites but I haven't found anything decent that I can buy in small quantity. Any help you can give would be appreciated.
Thanks Again,
Nathan

 

nfloyd, to find the right value dropping resistor you need to have some one who knows DC theroy figure the value for you.
Most LEDs are in the 2.5 volt dc range.
What you need is the series resistance value that will drop 14 volts to the operating level of the LED.
To do this, for example, look at the current the LED uses at it's rated operating voltage and use the simple formula
Resistance = voltage to be dropped divided by the LED current.
Or R= volts/ current
or R= 11.4/ .005 = 2300 ohms resistance .
This is just an example so work with whatever LED you intend to use.

 

Thanks Bluegrass,
Now I totally understand. I was looking at the calculator that SSCULLY pointed out to me, and I wasn't sure what to use in the equation for amperage, but now I realize it is the amperage draw of the LED itself. It all makes sense now!
Thanks again,
Nathan

 

It took me a few min to find a picture version of ohm's law ( what Bluegrass posted ).

http://www.ibiblio.org/obp/electricC...s/DC/DC_6.html

In his example, the LED has a resistance of 500 ohms.

Getting the LED that you are going to use, and checking the resistance is the starting point to figure out what the other reisitor size needs to be is a good starting point. Remember a LED is a Diode, if your meter does not show any resistance ( open circuit ), switch the leads around the other way, when taking the reading. The diode only allows the citcuit to operate in one direction.

What ever the LED that Signal Dynamics is using only needs a 330 ohm reisitor to get the correct voltage over the LED, which means it has a lower resistance then the 500 ohm or a higher voltage operating range, or a different current draw, then the example that Bluegrass posted.

Good luck if you are DIY on this.

For the switches, how much room do you have for mounting and do you mind cutting square holes for mounting, or preper round ?
That will give me a good idea which site to look at. Havinng a non LED indicator lamp sounds like a good starting point.

Steve

 

Thanks again SSCULLY,
I could just order the kits from SD and I may anyways, but I like to know what's going on and understand the theory. On the subject of rocker switches, I prefer rectangular and need switches that when mounted horizontally are no more than 1/2" top to bottom and the length doesn't matter. In other words, the dimension in the direction of switch throw is not as important as the dimension in the other direction, which needs to be 1/2" or less. The depth is not important either. I do want illuminated switches, though.
Thanks,
Nathan

 

Nathan,

Sounds like you would want to use a Cherry Rocker Switch ( that is the brand name ). Digikey.com has them, they are about 10.00 each. They are as good as Carling Switches ( bit too wide for your usage ), but have the illumination and size that you need.

These would be the LR or TR series switches.
http://www.cherrycorp.com/english/rockers/lr_rocker.htm

http://www.cherrycorp.com/english/rockers/tr_rocker.htm

Kind of pricey at 10.00 each switch, but these are going to look the most factory when installed.

Hope that answers your question, if not let me know.

Good luck.

Steve