How to determine which resistor to use for lighted switches?

[jtzako]

I want to use some of the illuminated switches (like SPST Momentary green ring Illuminated switch) and it says they have some resistor requirement. I'm not too familiar with how those work though. How do I know which resistor to use?

[IndustrialAction]

The easiest way that I've found is to use THIS (http://led.linear1.org/1led.wiz)site.

[jtzako]

So assuming a set of 4 AAA batteries is that still going to be 1.5 volts source? Or does it multiply based on # of batteries?

[Darth Xusia]

So assuming a set of 4 AAA batteries is that still going to be 1.5 volts source? Or does it multiply based on # of batteries?

Only in parallel, which wouldn't run anything. 4 1.5 Volt AAA batteries in series would be 6 Volts.

[jtzako]

OK, so according to that calculator, using the #s on the switch I mentioned I would need a 150ohm 1/8w resistor (which I dont see on the store here). I assume I could use the 150ohm 1/4w resistor as an alternate. (If I did the calculation right)

[Darth Xusia]

OK, so according to that calculator, using the #s on the switch I mentioned I would need a 150ohm 1/8w resistor (which I dont see on the store here). I assume I could use the 150ohm 1/4w resistor as an alternate. (If I did the calculation right)

That sounds right, depending on which switch you're using. I assume it's blue or green.
You can use 1/4 watt instead of 1/8 watt.

[Jedi-Loreen]

You can go above the resistor wattage that you need, but never below.