Can I use this Power Supply to run and test Laser Diodes?

[Verti]

Will this Power Supply be a good choice to run and test Laser Diodes?
Tekpower TP3005N Regulated DC Variable Power Supply, 0 - 30V at 0 - 5A
Adjustable outputs: 0-30V and 0-5A Variable controls for both current and voltage outputs
Input voltage: 110V
Regulation: CV <= 0.02% + 10 mV
Load Regulation: CV <= 0.02% + 5mV,
Ripple noise: CV <= 100 mVp-p
Protection: Current Limit
Environment: 0-40C, relative humidity < 80%




https://www.amazon.com/gp/product/B078MY5RGQ/ref=ox_sc_act_title_12?smid=AMH4W1K8OCGMX&psc=1

 

[paul1598419]

I am not familiar with this particular power supply, but from the stated specs, it could work. It depends on how well it will handle transients like turning the supply on and off and changing the current limit as laser diodes should be current limited. If you have an oscilloscope you should be able to test it for spikes that might kill a laser diode.

 

[Cyparagon]

Virtually all of them are okay, provided you power on (and power off) the PSU at zero volts and zero current and no load, then connect the load and adjust things tenderly. The power cycle is what can get you... or accidentally turning the pot too far.

An oscilloscope and test load setup would be required to verify the power cycles are safe.

 

[kecked]

It’s not a good practice and I’ve lost hundreds in diodes that way. Do it right.

 

[paul1598419]

I have tested many dozens of diodes using my tested power supplies and if you are careful and take your time these is no reason you should lose diodes to them. I have diode heat sinks and use these to test diodes for wavelength and threshold current. I have come across only two that were bad out of the box, but it wasn't because of my power supplies. I also use transistor sockets to connect to diodes so once they have been binned, they are returned in the same shape as I received them.

 

[kecked]

Lots of my lose wS from transient turn on. I bought a supply from mjpa. Turned out had a cap on the pout put that would let sthe voltage go to full on turn on. Gun shy now.

 

[paul1598419]

You never connect the PS until it is on and the voltage and current are at minimum. At the very least, if you are certain that your PS is free from spikes, you can turn it on connected as long as the voltage and current are turn down all the way. But, that is only if you are certain of this. I have to measure diodes by the score at times and not having a system in place to do it would take days to accomplish. I don't worry about my supplies as I have gone through them with a scope and ensured they are free from transitions like you have described. It works.

 

[lasersbee]

Wouldn't trust any of those PS types in the
OP until tested with a DSO for Turn ON/OFF
and running/controlling spikes/transients.

Jerry

 

[Verti]

Wow guys thank you for the great info, I am learning so much on this forum. From the info you guys gave me I decided to go with a Variable Linear DC Power Supply from Tekpower which is way more accurate and has much lower noise than the other one i was thinking about getting. I Scored it from Amazon on Prime Day for a great deal. It's regular price is $79.95 and I got it for $57.60 which is $22.35 off. I couldn't believe they had a Power Supply for sale on Prime Day. Here is a neat comparison of Linear vs Switching Power Supplies:


Here is the specs:
Model: TP3005T
Output DC Voltage: 0.0V – 30.0V
Output DC Current: 0.00V – 5.00 A
Input Voltage: 110V/AC, 60Hz
Voltage and Current adjustment
Voltage regulation: CV < 0.01% + 3mV, CC < 0.2% + 6 mA
Load regulation: CV < 0.01% + 3mV, CC < 0.02% + 3mA
Ripple and noises: CV < 1 mV rms, CC < 3 mA, rms
Protection: High current limiting and cooling fan.
Operating Temperature: 0 - 102 F (0 - 40 C), Relative Humidity: < 80%
LCD Accuracy is within +/- 2.5%
Size: 10 x 5 x 7 ¾ inches

Link
https://www.amazon.com/gp/product/B00ZBCLJSY/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

 

[Cyparagon]

Wow that chart is terrible. I guess the gist is roughly okay, but the specs are all wrong, and there's no reason that switching supplies can't be used in electrochemical applications. Virtually every lithium charger out there is switchmode, for example.

The best switching supplies have better regulation, noise figures, and transient response than the worst linear supplies. Also, assuming it was designed properly to begin with (I'm looking at you, china, with your sub $100 units), switchmode supplies are fine for all but the most sensitive applications.

 

[Benm]

The first one is definitely to be avoided, especially unsuitable to connect diodes to when the output voltage is above zero: You can see a fairly large electrolytic capacitor right across the output terminals (purple component on the bottom right in the 2nd picture).

For laser diode testing i'd stick with linear power supplies. Switchmodes aren't all as bad as in that table, but their main advantage over linear is lower weight and size.

Size isn't really a problem at the lower level required to test laser diodes though, a linear power supply that does 15V/5A doensn't have to be much larger than the switching one pictures, although it will be heavier due to both a heavy transformer and some additional heatsinking required (usually just fins on the back, some use a fan).