DIY | TESTER for LED TV BACK LIGHT

[bohaboha]

Hi I ask you if this Diy backlight tester does it really work? this uses a bridge rectifier exp: TS4b05 where test wires go from + and - then a resistance of 10k ohms on an AC input. according to the video it works but I would like your suggestions please
here the video:https://www.youtube.com/watch?v=LI6iudt2hgk

[megaraider]

Re: DIY | TESTER for LED TV BACK LIGHT

Yes... but only if you're felling lucky getting a 230V electric shock
Plus the resistor will keep burning

Stay SAFE and away from obvious hazards!!!

[Any decent rescued ATX power supply, or even a power supply adapter, will do the job]

[sam_sam_sam]

Re: DIY | TESTER for LED TV BACK LIGHT

I have safely concerns about your idea about building this device project
You need use extreme caution using this device if you do use caution using the device you have in mind then I do not see a problem doing it

However I would also think about using a VARIABLE TRANSFORMER

I have made a testing jig for testing 110 DC solenoids and I did something very similar I put in a plastic enclosure and alligator clips on for easy use

But I was fully aware of the risk of using this device
I have also made other testing jigs for testing devices that you have to use extreme caution using them

Just be aware of what you are doing when you this device

[bohaboha]

Re: DIY | TESTER for LED TV BACK LIGHT

Thank you megaraider and sam_sam_sam of corse i am looking to my safety

[momaka]

Re: DIY | TESTER for LED TV BACK LIGHT

YES, this tester will work... but it's NOT safe!

Let's do some simple math here. The video suggests to use 10k resistor in series with one of the AC legs on the bridge rectifier. With 220-240V AC, that limits the short-circuit current to:
I = V / R = 230 / 10000 = 0.023 Amps... or just 23 mA. (or 22 mA for 220V AC and 24 mA for 240V AC.)

Depending on the LEDs you're testing, 23 mA could be too much and burn out the LEDs.

But forget about the damn LEDs! 23 mA of current at line voltages of 220/230/240V AC is plain dangerous. That kind of current may be enough to not being able to let go if you happen to touch the any of the live parts. Worse yet, it's DC after the bridge rectifier, so your muscles may only clamp in one direction. Not to mention the guy in the video is holding the live wires with both hands - a good way to send a shock across the body.

Therefore, I don't recommend anyone to build a device like this. It's honestly a little more than silly. I do my fair share of silly crap too, but at the very least I never hold a high-voltage source with both hands, and I'm usually pretty well insulated from ground. If you really have to make a device like this, then use jumper wires to make connections before plugging in this "device"/contraption into the wall, so that you're not actually holding onto live circuits during testing.