The red driver

[Machro]

Come on guys , I think everybody of you is knowing that

 

[JLSE]

Unless you dont mind losing LD's, always test the driver first with a dummy
load.. Things get expensive when you accidentally blow an LD when you
can find any problems in a 3min test..

Even if a driver is rated for a low mA, and it 'shouldnt' give too much
current, a simple mistake in wiring can still send too much current.

Testing them first will save you headaches and money in the long run

 

[Machro]

Is the test load depending on the LD you wanna use , if so what are the schematics for a 808nm 300mw LD ?

 

[Machro]

IS this ok?

Heavy Duty Test Load Kit for Laser Diode Driver 3000mA | eBay

 

[JLSE]

You have to match the voltage of the diode you are going to use.. In this case
an 808 is around 2.2v.

Because its a low current you can use 3 x 1N4001 diodes in series with a
1ohm resistor.

All you need then is a multi meter to measure your current..

Have a peek around the forum, there is a lot of info on the subject.

 

[123splat]

It is a good habit to get into to ALWAYS use a test load to set/measure the current BEFORE hooking up your diode. Like what WANNABURN said. You can either measure Mv across the 1 Ohm (or so..) resistor and use Ohm's Law to calculate current, or you can connect your DMM, VOM, multimeter, in series with the test load and directly measure current (if you are really cautious, you can do the same when you hook up your diode,, put the meter in series with the diode and measure mA. there is no real danger to your LD, if you have set the current with a test load first). The only problem with measuring the current in series with the test load or the LD is if you are using a BOOST DRIVER. If the meter becomes disconnected a boost driver can/will go into runaway, and burn itself up. This is not a problem with a linear driver (like the one you first asked about). You should also have some load on the driver to get an accurate current measurement.