Do you have a technical question that doesn't really fit a specific console? Want some general info on electronics, hacking, making cookies, etc? Here's the place to ask! Go nuts.
Would these three parts work correctly together to make an LED flashlight if I follow this plan: http://www.instructables.com/id/SMJCJDYFDSE96EP/? Mainly, I'm concerned about voltage and stuff; that kind of thing is over my head.
Red light doesn't make your pupils dialate and affect your night vision. That's why the tail lights of cars are red. It illuminates, but unlike white light, you don't have to wait for your eyes to readjust to the darkness.
I use a red flashlight for just about everything. I just taped theatre light gels over the lenses.
This post brought to you by David Duchovny's glorious nipples.
Tibia wrote:Red light doesn't make your pupils dialate and affect your night vision. That's why the tail lights of cars are red. It illuminates, but unlike white light, you don't have to wait for your eyes to readjust to the darkness.
I use a red flashlight for just about everything. I just taped theatre light gels over the lenses.
i built me a small LED flashlight with a 3 AA battery holder, a potentiometer, a switch, a tact switch and five white LEDs. It worked great, but I don't actually have a real use for it, I was just bored
timmeh87 wrote:You are putting a resistor in there somewhere right?
This might sound stupid, but do I need one? The diagram that I was planning on following didn't have one, so I figured that I didn't need one myself. That's why I was wondering if the voltages (or whatever) of all the parts were compatible. Would the flashlight not work without a resistor?
If the LED's are rated to work at a lower voltage than a battery, then you need a resistor so you don't blow the LED's; if they match, ie LED 3v and battery 3v, all should be fine.
bacteria wrote:If the LED's are rated to work at a lower voltage than a battery, then you need a resistor so you don't blow the LED's; if they match, ie LED 3v and battery 3v, all should be fine.
That makes sense, but what do I do when I don't know the voltage? The "detailed description" under the LED doesn't mention voltage; it only says, "T1 3/4 (5mm) Red Jumbo LED with Diffused Red Lens, Standard Brightness. Prime, brand new. Package of 7. G1005." I found on the internet that most red LEDs take 2V. Would that be safe estimate for these LEDs?
Source voltage = the voltage of the batteries.
Diode forward voltage= the voltage of the LED (in this case, you're estimating 2v)
Diode forward current = the mA rating of the LED (T1's are generally about 30 mA)
If you're planning on using more than one LED, there's a link for calculating that on the same page. Hope it helps.
This post brought to you by David Duchovny's glorious nipples.
According to the battery information page, and according to my own experience, these batteries can't give enough current to blow the LED. So my advice is to go without a resistor. Or if you're worried, buy two LEDs and try using one of them without a resistor. If it works you can still connect both the LEDs to the flashligt.
Even if the battery doesn't have enough voltage to blow the LED, a resistor will help the LED last longer than it would without the resistor, so a resistor is always a good idea.
