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Electronics => Beginners => Topic started by: Ryanlg on January 27, 2012, 02:20:11 am

Title: Losing power off of a led
Post by: Ryanlg on January 27, 2012, 02:20:11 am
Hi guys,
This may seem like a pretty easy question. I have a project I have been working on, and I wanted to add a fancy switch and led to it. The main circuit of it requires 12v and I have 8 AA batteries in it. When adding a led I chose a red 12v flashing led from Jaycar. When I soldered it in in series, I was only getting 6v to my main circuit, instead of 12v. So I thought " stupid me it needs to be in parallel."so I soldered the led in parallel, but when the switch is turned off, the flashing led flashes.
Any suggestions guys how to get 12v to the main circuit with the led working properly.
Title: Re: Losing power off of a led
Post by: joelby on January 27, 2012, 02:30:44 am
Try putting the LED in parallel with the circuit, but on the circuit side of the switch, not the battery side. If it's still flashing when the battery is not in the circuit, you must have some other voltage source present.
Title: Re: Losing power off of a led
Post by: amspire on January 27, 2012, 02:32:27 am
Both the ways you connected the LED were wrong. The LED has to be in parallel with the other battery load. So one side of the LED connects to to the load side of the switch. The other side of the LED connects to the side of the side of the battery not going to the switch.
Title: Re: Losing power off of a led
Post by: sonicj on January 27, 2012, 05:32:10 am
here ya go
Title: Re: Losing power off of a led
Post by: Ryanlg on January 27, 2012, 05:38:09 am
Quote from: sonicj on January 27, 2012, 05:32:10 am
here ya go
Thank you!
Title: Re: Losing power off of a led
Post by: w2aew on January 27, 2012, 02:46:22 pm
...and don't forget the current limiting resistor in series!
Title: Re: Losing power off of a led
Post by: sonicj on January 27, 2012, 07:47:15 pm
Quote from: Ryanlg on January 27, 2012, 05:38:09 am
Thank you!
no problem!

and like w2aew mentioned, the resistor in series is important. 470? should be a good starting point.
-sj
Title: Re: Losing power off of a led
Post by: IanB on January 27, 2012, 08:01:48 pm
I think if it's a "12 V indicator LED" then the resistor will probably be built in.