Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

How to test whether a driver is safe to use with a particular diode?

brookcub

New member
Joined
Mar 17, 2020
Messages
1
Points
1
I recently harvested a circuit board from a generic DJ laser unit that has two drivers on it. One was powering a 50mW 532nm diode and the other was powering a 100mW 650nm diode.
4 - circuit board.jpg

I'd like to use this to drive a 55mW 488nm diode (Sharp GH04850B2G), but I'm not sure how test to make sure it won't get burned out.

I tried making a test load with a 1 ohm resistor and 5 1n4001 diodes in series, but the voltage drop across the resistor was only 0.0046V which seems really low. I might be doing something wrong.
91563488_870263800102175_2564718104235999232_n.jpg
91306838_893591091065894_3008585674149330944_n.jpg

Any advice would be greatly appreciated!
 





Snecho

Well-known member
Joined
Oct 2, 2019
Messages
826
Points
93
532nm is a DPSS wavelength and therefore isn't a diode.

I would just buy a nice new driver from DTR.
 

gazer101

Well-known member
Joined
Feb 23, 2020
Messages
700
Points
63
6 diodes (1N series, rated for your desired power) and 1 1ohm resistor (rated for your power) in series simulates the diode. Then hook that up to an ammeter in series and to a voltmeter in parallel and an oscilloscope. If the ammeter displays the proper current, voltmeter correct voltage, and the oscilloscope shows no spikes, the driver is safe to use.

EDIT: Make sure the diodes and ammeter are correctly hooked up to the driver (negative end of diode should connect to negative end of driver).
 

Snecho

Well-known member
Joined
Oct 2, 2019
Messages
826
Points
93
Yes, that build Lifetime made is really beautiful and you'll unlikely find a 488nm pointer that is as high quality as one of Lifetime's builds.
 

Anthony P

Well-known member
Joined
Oct 7, 2018
Messages
529
Points
63
Check all polarities. Maybe reading diode leakage (backwards).
 
Joined
Sep 12, 2007
Messages
9,399
Points
113
No. As evidenced by the lack of an inductor, this is a linear driver. With 5V in, you're going to be able to drive a 4V load at best reliably. I don't remember what those cyan diodes Vf is, but I'm pretty sure it's more than 4V.

Increasing the voltage might either fix it, or it may pop an IC on the board. I can't read the chips so I can't say for sure.
 

Giannis_TDM

Well-known member
Joined
Apr 27, 2019
Messages
894
Points
93
No. As evidenced by the lack of an inductor, this is a linear driver. With 5V in, you're going to be able to drive a 4V load at best reliably. I don't remember what those cyan diodes Vf is, but I'm pretty sure it's more than 4V.

Increasing the voltage might either fix it, or it may pop an IC on the board. I can't read the chips so I can't say for sure.
Yep vf on those cyans is around 6.3.-6.6v.
 




Top