2.1W "Evil Shadow" 650nm C-Mount Diode build Handheld

Sorry, I thought this was another one of
those fapril ool 'jokes'. I was not aware
the SXD could go up to 7 amps. Everyone
else was saying 5 MAX. And thanks for the
picture, too. It helps clear up a little
idea I was having amongst myselves.

VisibleGreen said:

Thanks you two for the info. Jayrob why did you use those 1n5404s?

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I followed the instructions from the driver manufacture with no questions asked. (Angelos)

For this specific set up (C-mount red), he wanted an extra layer of safety is what I figure...

About the 7 Amps, I did not test. Again, this was told me from Angelos. That it can do that.

Obviously the diode voltage vs supply voltage, etc... all come into play with what it can do, but he said that it can get to 7 Amps. 5 easily...

VisibleGreen said:

Thanks you two for the info. Jayrob why did you use those 1n5404s?

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jayrob said:

I followed the instructions from the driver manufacture with no questions asked. (Angelos)

For this specific set up (C-mount red), he wanted an extra layer of safety is what I figure...

Click to expand...

There are probably two reasons:

1) Most adjustable drivers use some form of voltage drop scaling, and typically that involves a second IC in the output current path. That second IC is often powered directly from the output current path, which means that if the IC has a minimum operating voltage of, say, 3V, it will struggle when used with loads (laser diodes) that drop less than 3V (an example being IR and RED diodes). Adding 1N5404 diodes is a way to add a little more voltage drop to the driver's output, so that the secondary current scaling IC has enough voltage to power up.

2) The cleanliness of a switching driver's output is impacted by the magnitude of the difference between voltage in and voltage out. A buck driver using lithium ions to drive a 445nm diode with a Vf of 5V will produce a cleaner output than the exact same driver setup driving a 650nm diode with a Vf of 3V, at the exact same current, all else being equal. Even though it doesn't seem like a big difference, it can be. Bucking from 6V to 3V involves 3x the differential of bucking from 6V to 5V. That means more ripple. Bringing up the output voltage may reduce the ripple, which is important on these sensitive diodes.

Hey I learned a few new things
I actually got a few of those diodes I bought on ebay once so I'm glad I will have a use for them.

VisibleGreen said:

Hey I learned a few new things
I actually got a few of those diodes I bought on ebay once so I'm glad I will have a use for them.

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Do you want to sell one? I bought one from cdbeam that turned up doa, so I'm still looking for one.

rhd said:

Do you want to sell one? I bought one from cdbeam that turned up doa, so I'm still looking for one.

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Sure send me your addy and I'll mail it out. Na no need for payment they're cheap.

VisibleGreen said:

Sure send me your addy and I'll mail it out. Na no need for payment they're cheap.

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??

You have to be talking about a different diode than what is shown in this thread right?

jayrob said:

??

You have to be talking about a different diode than what is shown in this thread right?

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Didn't he mean the 1n5404 diodes?

lol I guess he meant the C-mount my bad. Yeah would be awesome if they were cheap :crackup:
Sorry RHD I can't part with mine.

I haven't decided what I am going to do
with my C-mount. I ran into so many
problems with my build.

Now that there is a 638nm C-mount with FAC
and everything, I'm not sure why everyone
seems to want the old 660nm diodes all of a
sudden.

The Lightning Stalker said:

I haven't decided what I am going to do
with my C-mount. I ran into so many
problems with my build.

Now that there is a 638nm C-mount with FAC
and everything, I'm not sure why everyone
seems to want the old 660nm diodes all of a
sudden.

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Link please...

The Lightning Stalker said:

I haven't decided what I am going to do
with my C-mount. I ran into so many
problems with my build.

Now that there is a 638nm C-mount with FAC
and everything, I'm not sure why everyone
seems to want the old 660nm diodes all of a
sudden.

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Really a 638 cmount?? Like Jayrob said Link Please!

jayrob said:

Link please...

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I third that. Link please!

Is it the same diode you started a feeler for, then didn't tell anyone the manufacturer? Cause if so, I don't really think you can refer to them as "oh you know, those diodes everyone knows about." Not trying to be rude, but if you are going to keep talking about them, stop pulling our leg and throw us a bone [link]

Here are some pictures from the first test.
I haven't set up a sales thread or anything
just yet. If you want to talk about it or see
more pictures or anything, just send me a PM. :beer:

crazyspaz said:

Is it the same diode you started a feeler for, then didn't tell anyone the manufacturer? Cause if so, I don't really think you can refer to them as "oh you know, those diodes everyone knows about." Not trying to be rude, but if you are going to keep talking about them, stop pulling our leg and throw us a bone [link]

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Ya, I second that. That was really f'ing annoying.

And like I said, I'm not trying to be rude; but in a hobbyist community that's as small as it is, there really is zero point to just dangling something as awesome as 4 watts of 635 in front of people. Not only for us, but the projector guys at PL would salivate over those.