Help with a wiring job

JJPSY · 21-November-04, 04:41 AM

Hey,

I'm modding a digital monitor that runs off a 1.5v AA cell. I want to implement a 1.5v operating level LED light into the case.

Currently the negative and positive wires from the battery run directly into the circuit board. I want to keep it like this, and then I also want to run the LED light off the same battery, at the same time, but with it's own wires of course so I can mount it somewhere in the front case plate.

How would I wire this? I've thought about it and think you would need to do it in series but I have no idea really.

Any guru's that can give me some info on this?

hmspain · 26-November-04, 04:34 AM

First of all be careful that the forward bias of your led is indeed 1.5V. Blue leds have a forward bias of about 3.3V (as I recall).

Given that your monitor runs on a 1.5V battery, let's hope there are points on the circuit board that take advantage of a voltage doubler.

Do you have a multimeter? If so, poke around carefully looking for a voltage around 5V. I would not be too concerned about connecting an led (with the appropriate resistor in series of course). Typical leds run on about 20ma so the resistor would have to be about 200 ohms (a 1/4 watt will do nicely). (5-1.5)/.02

I hope this was not too vague and helps; I know how frustrating this can be :-).

TekXoID · 26-November-04, 05:30 AM

What on earth kind of display requires a mere 1.5v to run? B&W Gameboy?

Also, there is no such thing as an AA Cell, there is an AA battery, then
there is the common cell battery such as the CR2032 3.0v, which is it?

Either way, adding an LED will put a major hit on battery lifespan, if that display indeed requires
such little voltage I'm betting that an LED would probably use more than the actual display.

21-November-04, 04:41 AM	#1 (permalink)
JJPSY Apex Techie Wannabe Join Date: Nov 2004 Posts: 1	Help with a wiring job Hey, I'm modding a digital monitor that runs off a 1.5v AA cell. I want to implement a 1.5v operating level LED light into the case. Currently the negative and positive wires from the battery run directly into the circuit board. I want to keep it like this, and then I also want to run the LED light off the same battery, at the same time, but with it's own wires of course so I can mount it somewhere in the front case plate. How would I wire this? I've thought about it and think you would need to do it in series but I have no idea really. Any guru's that can give me some info on this?

26-November-04, 04:34 AM	#2 (permalink)
hmspain Apex Techie Lite Join Date: Nov 2004 Location: Cypress, CA Posts: 40	1.5V led First of all be careful that the forward bias of your led is indeed 1.5V. Blue leds have a forward bias of about 3.3V (as I recall). Given that your monitor runs on a 1.5V battery, let's hope there are points on the circuit board that take advantage of a voltage doubler. Do you have a multimeter? If so, poke around carefully looking for a voltage around 5V. I would not be too concerned about connecting an led (with the appropriate resistor in series of course). Typical leds run on about 20ma so the resistor would have to be about 200 ohms (a 1/4 watt will do nicely). (5-1.5)/.02 I hope this was not too vague and helps; I know how frustrating this can be :-).

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26-November-04, 05:30 AM	#3 (permalink)
TekXoID Banned Join Date: May 2003 Location: looking for love in the nearest gay bar Posts: 4,089	What on earth kind of display requires a mere 1.5v to run? B&W Gameboy? Also, there is no such thing as an AA Cell, there is an AA battery, then there is the common cell battery such as the CR2032 3.0v, which is it? Either way, adding an LED will put a major hit on battery lifespan, if that display indeed requires such little voltage I'm betting that an LED would probably use more than the actual display.