Test load help

Hey everyone..
I wanted to see if my flexdrives maintained the preset current before they were shipped to me by drlava. So I hooked up my 6 diode dummy load to the driver and measured the current across the 1 ohm resistor. I got 603 mA's with a 18650 cell. Then I used my other test load with 4 diodes for a LOC using the same battery. Using the second test load i got about 57 mA. My question is, what test load does dr lava use and how does he know which diode I want to use before he presets the current for us? In my situation, 6 diodes were what i needed. I am really confused here. Could someone explain what I am missing? i know that depending on the diode I am using, i need to use the correct amount of diodes for same vdrop. My questions might have been answered before.. I hope it's not a big deal to help me :/ Thanks.

did you ask for a preset range? or an actual preset current?


michael.

chipdouglas said:

did you ask for a preset range? or an actual preset current?


michael.

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I asked for a preset current at 600 mA. and the jumpers are at the last range..

BUMP! My question is: with a flexdrive preset by dr lava at 100 ma, is a phr and a LOC gonna receive the same 100 ma current? From my experience, the 2 diodes have different v drop, but WHICH will absorb 100 mA and what will the other one take?

I'm interested in this too.

I believe it'll provide 100mA regardless of the Vdrop, because it is a current-sourcing design that adjusts the voltage to whatever is needed. There's a feedback loop in these drivers that detects the current and adjusts what is produced. That's why it can burn up if there is no load, as it keeps trying to compensate for the error. The diodes in the load is there to provide a minimum voltage that the driver can provide, and a resistor to test the voltage on; the manual isn't specific about the exact number of diodes to test with.

The current reading you got with your LOC: maybe test it again? The resistor value too. That 57mA is below even the lowest setting a Flexdrive is supposed to supply (65mA) at any preset.

That makes sense, thanks for the explanation.

Bionic is right, it will output the set current for any diode load that is 2.2V to 5.5V, provided it's within the power envelope discussed in the manual.

drlava said:

Bionic is right, it will output the set current for any diode load that is 2.2V to 5.5V, provided it's within the power envelope discussed in the manual.

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So your saying a flexdrive will provide the same amount of current regardless of how many diodes are used in the test circuit? If I were to hook up 3 for a red I would get the same reading as if I were to hook up 6 for a bluray?

Kenom said:

So your saying a flexdrive will provide the same amount of current regardless of how many diodes are used in the test circuit? If I were to hook up 3 for a red I would get the same reading as if I were to hook up 6 for a bluray?

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If the input voltage would be enough yes