How to hook up 2 LED each with their own toggle switch to a battery?

im looking to install two toggle switches in my car. when the switch is placed in the on postion i want a LED light to turn on. I planning on using one red led light 1.8v 20ma and one yellow light 2.1v 20ma. Where im getting lost is the toggle switch has three metal tab label power acc and ground. Looking at using a 9v for the power source.

So what the best route to wire this up. Or should i just use a seprate power source for each light and switch.

As for the three tabs on the switch i guess that the postive wire goes to the power, but then would the acc go to the led postive side, and both the switch ground and the led ground go to the point on the power?

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wkter7 years ago
No, you do not need separate power sources for the LEDs. You're not really clear on wheter you want both LEDs to light up when you switch it on, or you want just one LED to be lit at a time, so I assume you want one LED to be lit at a time.

For the switch you have, it should work something like this; Pin 2 (2nd pin from the left) is where you want you power connected, so when the switch is positioned to the left, the power will flow from Pin 2 to Pin 1, and when the switch is in the right position, power will flow from Pin 2 to Pin 3.

Use this image for reference on how the switch works.

Because you have a 9v battery, you cannot simply solder the LEDs to pin 1 and 3 on the switch; the LEDs would be fried! So what you need to do is to add some limiting resistors. Using this site for calculating what resistors you need, you now know that you must place a 390 Ohm resistor on each of the LEDs. When you have done this, you can solder the LEDs to the switch. Finally, you must solder the LEDs to ground.

Here you have a schematic that should work for you.

I hope I didn't make this even more confusing for you!
mobow213 (author)  wkter7 years ago
Sorry for not being clear But i would like for both LED to have their own switch. Basically im looking at using some safety toggle switch to put in my car and label them as different stuff.

So after reading and learning here i was thinking i can run the power of the battery to the 1st switch, then run power from there to the second switch. Then route the power from both switches ACC pong to the resistor then the LEDs. The ground from each LED would go back to their own switch. Then the ground from switch 2 would go to the ground on switch 1. With the ground from switch one going to the battery
wkter mobow2137 years ago
Ah, I see.

Doing it that way, you actually only need to care about 2 pins on the switch, and just forget about the last one. Considering that switches aren't polarized (Obviously), it's not a big deal what pins you use for what. I like using the pin in the middle for my power, then output on either pin 1 or 3.

I've updated the schematic to use 2 switches.

I would recommend you getting a lower voltage source so you can to some experimenting without risking frying your LEDs, and when you have a working circuit you add the resistors and your 9v source.
frollard wkter7 years ago
Awesome answer ^

One thing to think about, is it might be a lit up toggle switch, 3 pins but only single pole single throw on the other 2, common ground.
caarntedd7 years ago
The toggle sort of points to the tab that is on. That is if the toggle is up the bottom tab is on. If the toggle is down the top toggle is on.
If you want the toggle to be off in the up position and on in the down position, connect a wire from the positive of the battery to the centre tab, a wire from the top tab to the LED, and from the LED to the negative of the battery. Swap from the top tab to the bottom tab if you want the switch to work in the oppposite direction.

I think the battery voltage may be a little high for an LED without a resistor.