need dummy load for PHR-803T diode

Hi all,

Quick question for the electronics experts. I have DDL's PSU which comes with a voltage and amperage adjustment pot. I have a 1 ohm resistor connected in series at the output. I now need to solder on a dummy load so that I can adjust the voltage and amperage before hooking up the PHR-803T. Could someone please recommend a cheap dummy load?? Someone was suggesting using 4 x 14N001 diodes or something like that?


Many Thanks.

Don't forget to tell Rog , "thank you"

Peace,
dave

I thought the search button would find this graph. or not?

Thank you Rog!!! Thanks daguin

Silvershot, didn't know what to search for hehehe.

Many thanks all!

Or you could just hook up the output of your driver to an ampere meter, which any decent voltmeter/multimeter should have now days?

your mom is an ampere meter!

...i love making useless posts

Mohrenberg said:

your mom is an ampere meter!

...i love making useless posts

Click to expand...

My mom happens to be deceased....

Thanks for your "useless" post, jackass....

I you can't find the 1 Ohm resistor for the Test Load
circuit you can look here...

http://laserpointerforums.com/f39/free-1-ohm-test-load-resistors-42409.html

BTW... the Test Load procedure has been time proven
right here on the Forum to be the safest and surest way
to test and set a Laser Diode current Driver...


Jerry

thanks lasersbee

Here's a cool little build I did this morning, based on our good friend ROG8811's designs...

I decided to put the dummy load circuitry (refer to msg 2 above) in a little plastic project box, so I pulled a few plug sockets, a couple of IN4004 diodes and a 1 ohm resistor and wired them up on a PCB. First thing was my hunt to find a proper 1 ohm resistor. I have plenty of 1/4 and 1/2 W units but needed something more powerful. So I went into my box of power resistors:

Who says it's a waste of time to retrieve the boards off old TVs and monitors... LOL!
Then I drilled on the drill press five holes on the sides of the box to make room for the banana plug sockets. I isolated the connectors of the plugs with shrink tubing to avoid shorts.

After everything was wired, I started working on the board, which I cut-off to size with a dremel cutting disk... it fits perfectly into the project box.

I left the diode wires a bit longer and soldered them not too tight to help in the heat dissipation. The resistor is a 5 watt unit so its a bit of overkill...
Then I wired the board to the plugs and squeezed the components tightly into the box and applied a bit of glue to prevent the board from rattling in the box and avoid possible shorts.

Then I went on the komputor and did a cool little connector identification label. Thanks Rog8811 for that schematic! Voilà:

Total cost of build: about $5, the banana plugs being the most expensive items in the build. The project box is only $1 at the electronics shop where I go. The diodes were $10 for a thousand and the resistor was probably retrieved from a defunct TV years ago.
Robert

roddenberry:

That's a very handy and neat build. Well done and many thanks for sharing with LPF

Always a pleasure... I don't spend nearly as much time as I would wish on my electronics hobby. On September 14, i'll have all the time I need to enjoy my laser tinkering hobby. For now I have to go through this in the next few days:
FMPM.NET - Le Festival des Musiques Progressives de Montréal
I'm one of the organizers of that event.

Robert

Hey I just noticed you're using a 5w resistor. I've got a spare 3w (I think) that looks a bit like yours. I should try using that because I'm getting weird readings on my dummy load now hmm... why did u say that 1/2 or 1/4 watt wasn't sufficient?? What happens if the driver overloads the resistor?

Btw, all the best for your event and hope it all goes well for you.

roddenberry said:

I have plenty of 1/4 and 1/2 W units but needed something more powerful.

Click to expand...

Very nice & neat build. Just out of curiosity, why did you need something more powerful than 1/2 Watt?

cyclonite said:

What happens if the driver overloads the resistor?

Click to expand...

It dies...you'll know when it dies. It'll give off a very fowl smell (Kind of smells like burnt plastic), and will be insanely hot to touch (Like burn your flesh hot). I doubt you'll fry a 1/2 Watt resistor though with using it in a test load, unless you're setting the current for Dr. Evil's moon laser...

ahh ok so the problem that I'm faced with isn't an overloaded resistor... hmm...

mfo said:

Very nice & neat build. Just out of curiosity, why did you need something more powerful than 1/2 Watt?

Click to expand...

Thanks! Well i figured just to be on the safe side when using the load at the high end of the power scale (if that ever happens) might make the resistor a bit warm so that way it won't ever overheat ! LOL But you're right a 1/2 W unit would have been fine for the purpose i'll use it for.

I also had a 50 watt wirewound on ceramic core 1 ohm resistor but that would have been overkill to the max! :evil:

Robert