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Testing the mA and a dummy load?

FokoF

FokoF

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Right........... I'm building a TTL module with a 803t diode and a Flexmod lava driver.... Questions...

1. How do I test mA with a multimeter.. series? parallel? etc...

2. Testing the mA without the diode and using a dummy load instead, how do I do it? I've heard of using 4 LEDs in parallel, instead of the diode....

3. The DDL driver, what is the max mA it puts out? (what to make it TTL to drive a red and another 803t)

Thanks!
 





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ArRaY

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I recommend you to build a dummy/test load.
This is easily accomplished by putting 4 1n4001 diodes in series with a 1 ohm resistor in series.
Current is then measured in parallel to the 1 ohm resistor with the mV range of your DMM, where 1mV equals 1mA.

Max output is depends on your batterys, and the package type of you lm317. Whereas the max (uncooled) output of the TO-92 is 100mA and the max output of the lm317T is 1,5 A.

You want an input voltage of 7.2 V for a red diode and 10.8 for a 803T.
No idea on TTL though, but i would think about someting like an optocupler...

ArRaY
 
FokoF

FokoF

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Duty cycle on a 803t in a aixis housing and in a 40x30mm milled alu heatsink? :-?
 
TheGr8Revealing

TheGr8Revealing

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i typically run all of my 803t's for less than a minute at a time. then i give them 15-20 seconds to cool. It may also help to put some heatsink compound between the two aixiz parts.

:)
 
FokoF

FokoF

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I want to use it in a scanner, so it has to be able to run for hours... Heatsink is nearly done.. Might add a 40mm fan to make sure it doesnt blow....
 
FokoF

FokoF

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At uni at the moment... So no can do till the weekend... But the heatsink is beautiful!:) i love steel lathes!
 
FokoF

FokoF

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Here is the heatsink :D with a fan, hoping to get 100% duty cycle
 

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iNiels

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u could make a cube heatsink and at a Peltier to cool it. Then add another heatsink to the warm side of the peltier. Think this will give you good duty cycle
 
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boxmour

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hey um. i bought like 10 x 1n4007 1000v 1amp diodes..i was just wondering if they would work similar to the 4001 diodes as a test load?
thx
kurt
 
TTerbo

TTerbo

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hey dude my phr <<<<in my avatar.
has a duty cycle of 100% its heatsink is 50mm in dia. and however long i made i cant rememmber. you wont need the fan.
the max output of a ddl driver depends.
you can modify the resistance to get different outputs. like a ddl driver with no 1n400* diode and a 12 ohm resistor in its place will out out 100mA just right for a phr (thanks eudaimonium for this knowledge :p)
my phr is running on 103.5mA.
cheers
 
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