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help with making a test load

P

plasmaninjaa

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Hey guys. I feel like an idiot for posting this because i'm sure it has been posted a million times.
I can't seem to find instructions on how to make a testload for my driver.

I have a 9mm 445nm diode and the blitzbuck v3.1 driver.
The driver is adjustable and I want to set it to 2.3a

please help! sorry for the idiocy
 





ARG

ARG

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Diagram
TestLoad445nm-405nm.png


Parts:
1N5404 diodes rated for 3A or greater
1 Ohm 10 Watt resistor (2% tolerance or less)
You can replace the 1 Ohm resistor with a 10A ameter if you want a better accuracy.
 
P

plasmaninjaa

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so just hook up the ammeter between the first diode and +ve and turn the dial on the driver until I get 2.3a on the ammeter?

because i dont have any 1ohm diodes.
I have a pot but the lowest resistance I can set it to is 4ohms



ARG said:
Diagram
TestLoad445nm-405nm.png


Parts:
1N5404 diodes rated for 3A or greater
1 Ohm 10 Watt resistor (2% tolerance or less)
You can replace the 1 Ohm resistor with a 10A ameter if you want a better accuracy.
Click to expand...
 
ARG

ARG

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plasmaninjaa said:
so just hook up the ammeter between the first diode and +ve and turn the dial on the driver until I get 2.3a on the ammeter?

because i dont have any 1ohm diodes.
I have a pot but the lowest resistance I can set it to is 4ohms
Click to expand...

Yup, that will work.

Edit: Referring to the use of an ammeter, obviously a pot will not work.
 
Last edited:
lasersbee

lasersbee

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plasmaninjaa said:
Hey guys. I feel like an idiot for posting this because i'm sure it has been posted a million times.
I can't seem to find instructions on how to make a testload for my driver.

I have a 9mm 445nm diode and the blitzbuck v3.1 driver.
The driver is adjustable and I want to set it to 2.3a

please help! sorry for the idiocy
Click to expand...

The Search Bar is your friend...

LPF Google Search Bar

Just enter what you are looking for...


ARG said:
plasmaninjaa said:
because i dont have any 1ohm diodes.
I have a pot but the lowest resistance I can set it to is 4ohms
Click to expand...

Yup, that will work.
Click to expand...

BTW... You can't use a standard pot to replace the
1 Ohm Test Load Shunt resistor.
A standard pot can't handle 2.3 Amps of current
without burning out.


Jerry
 
Last edited:
TheDukeAnumber1

TheDukeAnumber1

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plasmaninjaa said:
so just hook up the ammeter between the first diode and +ve and turn the dial on the driver until I get 2.3a on the ammeter?

because i dont have any 1ohm diodes.
I have a pot but the lowest resistance I can set it to is 4ohms
Click to expand...

Your not quite reading the schematic correctly there. IMO, these are great

http://laserpointerforums.com/f39/fs-selectable-test-load-up-3a-assembled-diy-kit-stock-63450.html

or try raising the drivers pot to a high resistance, then run the laser and adjust it on the fly measuring the Amps with a DMM. GL
 
Last edited:
Cyparagon

Cyparagon

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Sep 12, 2007
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ARG, that configuration will drop over 7 volts at 2.3A. There's some myth going around that diodes always drop 0.7V. And if that isn't bad enough, people always forget about the drop on the shunt. Please don't perpetuate this misconception.
 
Last edited:
phenol

phenol

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Oct 30, 2007
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Regular PN junction diodes may drop well above 1V at elevated currents, but the drop itself will ...drop...as junction temperature increases.
Schottky diodes offer lower forward voltages.
 
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