# Help with simple led wiring

## Main Question or Discussion Point

Alright I need help. I am not electrically inclined so figure this is the best place I could have come. I'll make this as simple as possible.

I have:
1 Red 5 mm LED with specs 2.6V - 28mA * 10mcd
1 Green 5mm LED with specs 2.1VDC - 25mA - 6.3mcd
9V battery as source

What I need.

Need to wire this so that the green led is constant on and when a switch is depressed the green turns off and red turns on then if the switch is released back to green.

that is the switch I have.

Thanks so much for your help!

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Redbelly98
Staff Emeritus
Homework Helper
I have attached a circuit that should do what you want.
The 330 ohm resistors will give about 20 mA through each LED.

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Redbelly98
Staff Emeritus
Homework Helper
rougeqc21, I should probably ask by what means you would be making connections in your circuit? I.e., soldering, or using wires with alligator clips (available at Radio Shack), or a solderless breadboard, or other?

Feel free to post if you have more questions.

Thanks for the help redbelly.

I will be soldering it all myself, that at least i am proficient at haha from hobby related endeavors. Would that switch I had the link to work? I hooked pos and neg from the 9V and it seemed like it was just shorting the battery out (it was getting very hot)

Redbelly98
Staff Emeritus
Homework Helper
If you hooked the switch up directly to the battery, then yes you were shorting it out.

I can't find a wiring diagram for the switch at Radio Shack (not surprisingly), so I can't answer for certain that it will work. But it is listed as a spdt 3-lead switch. So one lead (probably the center one) is always connected to one or the other of the other 2 leads. That lead is what gets connected to the battery. As for rest of the connections, see the circuit diagram I posted earlier.

I'll suggest getting some wires with alligator clips just so you can verify and debug your circuit before you start soldering things. You can waste a lot of time desoldering and resoldering if things are not connected correctly. I saw the clip wires at my local Radio Shack earlier today, they come in a package of 10 and might cost $5 or at most$10.

As a start, connect 1 LED and resistor to the battery leads to satisfy yourself that things will work. This will also tell you the polarity of the LED (which wire is +).

Reminder:
By using 330ohm resistor, it rates to 27mA (not 20mA) for 9VDC. It should be 360ohm for both (25mA and 28mA)

Redbelly98
Staff Emeritus