Why a driver?

[mays]

Hi, I've been into this laser thing a while now, and since I' considering to build my own, I have a question...

Why do i need a "driver" and that stuff? I mean, if I get a laser diode, why can't i simply fix an output of 3V 50mA, connect it directly to the laser diode, and get an output of about 60mW?

Thanks

 

[BShanahan14rulz]

I mean, if I get a laser diode, why can't i simply fix an output of 3V 50mA, connect it directly to the laser diode, and get an output of about 60mW?)

How will you simply fix an output of 3V 50mA? "Wires? Please only let 50mA of current through. Thanks!"

Driver is a word for the circuitry that does what you are talking about.

 

[mays]

How will you simply fix an output of 3V 50mA? "Wires? Please only let 50mA of current through. Thanks!"

Driver is a word for the circuitry that does what you are talking about.

If I have 2 x 1,5V batteries in series, and then connect a 60 Ohm resistor, that should give
I = U/R = 3/60 = 50mA.

I guess I am wrong, but why? Oh, and if i DO find a battery charger with the specs "3V, 50mA", then it should work, right?

 

[RA_pierce]

If I have 2 x 1,5V batteries in series, and then connect a 60 Ohm resistor, that should give
I = U/R = 3/60 = 50mA.

I guess I am wrong, but why? Oh, and if i DO find a battery charger with the specs "3V, 50mA", then it should work, right?

Yes, you can use internal resistance in the batteries as well as added resistors and resistance from the host to limit current.
But we like to use drivers here. For one, they even out voltage spikes. Adding a capacitor to your setup is a good idea. Spikes can kill your diode. Also, a buck/boost driver gives the user a wide range of current range selections and makes the laser compatible with a wider variety of power sources. Also, when driven directly off batteries, the power will drop as the battery drains. A driver like the Flex will use up all of the battery's charge until it drops out of regulation (<2V) while maintaining a constant current.

 

[mays]

Yes, you can use internal resistance in the batteries as well as added resistors and resistance from the host to limit current.
But we like to use drivers here. For one, they even out voltage spikes. Adding a capacitor to your setup is a good idea. Spikes can kill your diode. Also, a buck/boost driver gives the user a wide range of current range selections and makes the laser compatible with a wider variety of power sources. Also, when driven directly off batteries, the power will drop as the battery drains. A driver like the Flex will use up all of the battery's charge until it drops out of regulation (>2V) while maintaining a constant current.

Ok, thanks! When i get a driver, what else is there to worry about? Cooling? Host?

 

[chipdouglas]

for running 50ma or trying to get even 60mw.... you dont really need extra cooling other than the aixiz module and the host you put it in, assuming it is a metal host, preferably aluminum

michael

 

[lasersbee]

Hi, I've been into this laser thing a while now, and since I' considering to build my own, I have a question...


Ok, thanks! When i get a driver, what else is there to worry about? Cooling? Host?

to the Forum...
Don't forget to read the Newcomers section... the FAQs....
the Stickies and the Forum Rules....

Not from what I've read.....

Read and use the info I just stated above and also read the
Laser build tutorials found on the Forum..
They are indispensable to learn about building your own Laser..


Jerry

 

[millirad]

^ What he said. You must read the stickies! I'll just give you one pointer though. You must short out the output capacitor of your driver or the stored voltage will "immediately" kill your laser diode. Welcome to the forum.

 

[mays]

to the Forum...
Don't forget to read the Newcomers section... the FAQs....
the Stickies and the Forum Rules....

Not from what I've read.....

Read and use the info I just stated above and also read the
Laser build tutorials found on the Forum..
They are indispensable to learn about building your own Laser..


Jerry

Thanks, I've read the "build your laser" threads now, really helpful

Haha, you're right... Well, I've had red, green and blu-ray handheld lasers a while now, but it's now recently that I've started reading of how lasers really works.