Dummy load for high current - 2A test load and 3A

Aha. I appreciate your help SHIN.

Now how does accuracy work on the dummy loads? By that I mean if the voltage drop of the dummy is different from the voltage drop of the diode, will that effect the loads accuracy? Or does it just need to be as close as possible?

Why exactly can't the flexdrive v5 supply 1.5A to the diode? I'm no electical engineer haha so I don't FULLY understand the concepts at work here. Please SHIN, explain...

Thanks,
Blaine

My specialty is way from electronics, too.

One day, I tried to set v5 with 445nm LD at over 1.2A but could not set over 1.2A.
I asked drlava about this and he replied so.

And this is described (as a equation) at last lines of drlava's v5 manual.

I'm waiting drlava's "v6" that could kill 445nm LD...

SHIN

Gotcha. Well that works for me for now since, like I said I'll be setting mine at about 1.1A.:yh:

Again though SHIN, thanks for your help.

You're welcome.

Only remember to use wires and jumpers that can hold the 3A current without melt or burn .....

BTW, 1N5404 = BY255 = S3G-57T = 1N5624 = 31DF4 = BY397 / BY399 = EGP30G = FR305 = HER305 = MR852 = NTE5802 = SF32 = 30S2E3 = MR851 .....

All these diodes have 3A and at least 100V (some of them also more, but for use as load is not important, as far as it's over the maximum useable voltage), and any of them can be used ..... if you don't find a specific part number in your zone, maybe another one can be found more easily (only, don't mix different part numbers in the same load )

Thanks. HIMNL9.
I would like to burn my test load if there are 3A drivers and 3A laser diodes.

SHIN

I post a PDF data file of 1N54xx.
I hope the voltage-current graph (Fig.3) will be helpful for accurate calculating the drop-out voltage with 1N54xx.

1.1-1.2A --- 0.8V
2A --- 0.85V
3A --- 0.9V

Re: Dummy load for high current - 2A test load

SHIN said:

PS) Hi. jmgallego.

That's a good idea. I made one as you suggested.
Resistor selector- upper(200milliohm, upto 3A, 5 x V = I), lower(1ohm, upto 2A, V = I)

Click to expand...

Glad to hear

Built a few myself too...

What are those gates called? The ones with connected to the diodes that have 2 prongs in the air that a female jumper goes over to connect them.
I am looking to buy them and I know they aren't called jumpers or gates but I lack the correct terminology to identify them ^_^

AUTO XX said:

What are those gates called? The ones with connected to the diodes that have 2 prongs in the air that a female jumper goes over to connect them.
I am looking to buy them and I know they aren't called jumpers or gates but I lack the correct terminology to identify them ^_^

Click to expand...

Breakaway headers? You can put a jumper over them to connect them together electrically.

You are THE man Bionic-Badger!
I spent about 1/2 hour looking up everything I could think of and all I was getting was rows of them that were non-breakable
Nice looking dummy loads guys, I already have parts on the way to finish mine

Sorry to bring up this old thread, but are you guys including voltage drop across the resistor in the dummy load (if you use the resistor in the dummy load) when determining the number of rectifiers to simulate Laser Diode?

I mean lets say you are testing Clapio 445nm diode at 1A current ad at that current it has a forward voltage of 5V (just a figure number, not sure what it is exactly) so you are setting 1n5401 diodes (which at 1A have ~0.7V forward drop).

You would set 7 of 1n5401 diodes which will add up to 4.9V drop. But your 1 ohm resistor shows 1V drop (which is equivalent to 1A of current) so it means that your actual drop across the entire load is 5.9V.... Thus you need 6 diodes not 7 (6*0.7V + 1V=5.2V)

So I think people need not use the universal prebuilt dummy loads but calculate and adjust the custom test loads on the breadboard or something taking into account current, Vf of diodes at that current and Vf of the resistor at the current prior to each and every build.

Hi. gillza.

You're right.

The drop-out voltage at resistor in low current is negligible relatively.
But high current causes much more voltage drop at resistor and rectifier, so new calculation and high-current parts are needed.
If one uses prefixed test load for lower current in high current, serious error in current setting of the driver will occur and this may kill the LD.

Previously I experienced two same "freak" 445nm lasers that set with prefixed low-current test load.
Output power far more than other member's laser embarrassed me.

Now I know I was "lucky" because if V5 could supply far more than 1.5A, my LD might not survive.

SHIN

How many diodes to use? I found this which explains it very clearly:
Laser Driver Set-up - OdicForce Lasers Online Shop

Omg, stop necro posting....