- Joined
- Dec 27, 2011
- Messages
- 2,062
- Points
- 48
I am terribly behind on so many things right now, it is frankly embarrassing. This is one of those things. Tom has sent me several FMT drivers to test and I've had several problems on my end - finally I have one that I haven't killed and is ready to test... and I have finally gotten around to testing it today.
I'm open to suggestions from experts on oscilloscopes if there is anything I am doing wrong, but I have done a few of these now and this was very promising.
First, here is my setup... I have a custom built test load with some serious heat sinking with heat-sinked TO-220 8A diodes and a 60W 1% 1 ohm resistor + 80, -20ppm/°C resistor that is also highly heat-sinked.
I have selected three of the diodes for this test. I have a Tek TDS210 with a 82003 DMM attached to the output posts.
I have also attached at heat sink to the back side of the FMT driver for this test, although at ~500mA it never got warm.
I was using a mix of a cheapie trust/ultra/whatever-fire and a good AW IMR 14500 Li-Ion cell in series for 8.4V of output (edit: from the battery pack to the driver, or more commonly known as input)
Test Load by tsteele93, on Flickr
First the output, it seemed to be falling a bit as the batteries started to drain - these drivers seem to pull some serious current - I did not test that though.
Basic Output by tsteele93, on Flickr
Here is startup in DC mode - to show the startup spike - or lack thereof...
FMT startup by tsteele93, on Flickr
I set the baseline to the second line up from the bottom and the divisions are 100mV per line, so as to use as much of the screen as possible.
Virtually no spike on startup at all.
Next I took a picture of the the oscilloscope running with NO INPUT - just noise attached to the output pins of the test load with no input, in AC mode. So the DC is removed and we ignore any positive voltage. In this instance, there is NO voltage, so all we are seeing is the oscilloscope noise.
No Power - Oscilloscope Noise by tsteele93, on Flickr
Then I turned on the driver and waited for the scope to filter out the 500mV of positive voltage and just show the AC ripple... of which there is none. It looks just the same as when the driver is turned off. The only difference is that there is ~494mV of positive voltage which we aren't seeing here because of the AC setting on the scope.
FMT Driver turned on with 494mA current by tsteele93, on Flickr
These are for sale at cajunlasers.com (although I think the hurricane has things out of order for the time being and they seem like a very stable driver. You can contact Tom (aka FoulMist) here on the forums via PM for any questions you may have and there is a nice thread on his drivers in the forum as well.
I have no connection to these drivers, monetarily or otherwise, and I even paid for this driver that I tested - so full disclosure is that I have nothing to gain from any of this - just reporting my findings to the forum. And I would encourage anyone else with the resources to do the same.
I also would encourage anyone with any ideas of how I could do better, or anything I might have done wrong or other tests that you would like me to do - please let me know as I would like to be able to test any drivers I can test and report back to the forum.
Thanks for looking!
I'm open to suggestions from experts on oscilloscopes if there is anything I am doing wrong, but I have done a few of these now and this was very promising.
First, here is my setup... I have a custom built test load with some serious heat sinking with heat-sinked TO-220 8A diodes and a 60W 1% 1 ohm resistor + 80, -20ppm/°C resistor that is also highly heat-sinked.
I have selected three of the diodes for this test. I have a Tek TDS210 with a 82003 DMM attached to the output posts.
I have also attached at heat sink to the back side of the FMT driver for this test, although at ~500mA it never got warm.
I was using a mix of a cheapie trust/ultra/whatever-fire and a good AW IMR 14500 Li-Ion cell in series for 8.4V of output (edit: from the battery pack to the driver, or more commonly known as input)
Test Load by tsteele93, on Flickr
First the output, it seemed to be falling a bit as the batteries started to drain - these drivers seem to pull some serious current - I did not test that though.
Basic Output by tsteele93, on Flickr
Here is startup in DC mode - to show the startup spike - or lack thereof...
FMT startup by tsteele93, on Flickr
I set the baseline to the second line up from the bottom and the divisions are 100mV per line, so as to use as much of the screen as possible.
Virtually no spike on startup at all.
Next I took a picture of the the oscilloscope running with NO INPUT - just noise attached to the output pins of the test load with no input, in AC mode. So the DC is removed and we ignore any positive voltage. In this instance, there is NO voltage, so all we are seeing is the oscilloscope noise.
No Power - Oscilloscope Noise by tsteele93, on Flickr
Then I turned on the driver and waited for the scope to filter out the 500mV of positive voltage and just show the AC ripple... of which there is none. It looks just the same as when the driver is turned off. The only difference is that there is ~494mV of positive voltage which we aren't seeing here because of the AC setting on the scope.
FMT Driver turned on with 494mA current by tsteele93, on Flickr
These are for sale at cajunlasers.com (although I think the hurricane has things out of order for the time being and they seem like a very stable driver. You can contact Tom (aka FoulMist) here on the forums via PM for any questions you may have and there is a nice thread on his drivers in the forum as well.
I have no connection to these drivers, monetarily or otherwise, and I even paid for this driver that I tested - so full disclosure is that I have nothing to gain from any of this - just reporting my findings to the forum. And I would encourage anyone else with the resources to do the same.
I also would encourage anyone with any ideas of how I could do better, or anything I might have done wrong or other tests that you would like me to do - please let me know as I would like to be able to test any drivers I can test and report back to the forum.
Thanks for looking!
Last edited: