what's a laser diode driver?

Hi guys! Sorry for the stupid question, but when i searched in google what's the job of a laser diode driver, i couldn't find anything helpful. So far i have made a circuit using a laser diode, batteries and a resistor. Can someone help?
thanks :thinking:

''...when i searched in google what's the job of a laser diode driver, i couldn't find anything helpful''

You're kidding right?

I can't belief you diditn find it in google but I'll tell you anyway
A laser diode driver is a constant current regulating device that supplies a constant regulated current and voltage and thus keeping your diode running happily
Thats the simplest I could explain it hope I could help.

and what happens if i don't use a driver and i just use my batteries and my diode?:anyone:

You will blow up the diode. Simple as that.

Blord said:

You will blow up the diode. Simple as that.

Click to expand...

Couldn't have said it better myself.....BOOM there goes your money, diode and hard work

So, every time i have to choose a driver which is as mW is the laser diode?
For example, if i use a 200mW laser diode i also have to use a 200mW driver?

Here is a good link that explains more the why rather than just the driver options that are available. It is an old article but still a great read for newcomers.:beer:
Laser driver - It can be done

thank you guys, but you still don't answer my question. Every time i have to choose a driver which is as mW is the laser diode? (i am not talking about homemade drivers).

Which diode? if you tell me I can answer your question

The number in the diode is the maximum power. So a 200mW diode can handle any power till 200mW. The power will be set by the driver, not the diode.

apoelistas77 said:

Hi guys! Sorry for the stupid question, but when i searched in google what's the job of a laser diode driver, i couldn't find anything helpful. So far i have made a circuit using a laser diode, batteries and a resistor. Can someone help?
thanks :thinking:

Click to expand...

One of the best first questions I have seen so far. Usually we get, "where can I get a laser that will start my school on fire?" or "how many watts does it take to blind someone I don't like?"

Your question isn't stupid at all!

Also, different diodes require different voltages AND different currents. As a rule, the longer the wavelength, the lower the voltage. It will also depend on what kind of battery you want to use.

If you want to use two 3.7 v batteries to drive a red diode then you need a driver that can buck (decrease) the voltage in addition to supplying the correct current for the diode.

If you want to use a low voltage setup, lke two AA's at a total of 3v then you need a driver that can boost (increase) the voltage as well as provide the correct current for the diode.

Hang on, I'll get a post that explains it really well.

EDIT:.http://laserpointerforums.com/f67/f...river-tested-working-71433-8.html#post1033246

apoelistas77, are you from Cyprus? Welcome, btw...

Diodes (laser diodes) are current driven devices. The driver is like a tube in a water system.

It restricts the flow of the water (current) to the diode (sprinkler) so the top doesnt blow off with the pressure (too much current).

In the case of a laser diode, they usually have a spec sheet that is either delivered with the diode, or can be found online. The sheet tells you what size pipe to fit between the tap and the sprinkler (what the maximum current the diode can handle before going POP!). A driver has a potentiometer or pot. You adjust this pot to set the current to the recommended value. This is like getting the right sized hose for our sprinkler analogy.

Once the potentiometer is set, there is usually no further reason to change it, hence on 99% of laser pointers, you wont find a knob to adjust.

Pot modding (the act of increasing the water flow, or current) was one way of getting more power out of a cheap ebay green, at the expense of shortening the diode life, or possibly simply blowing it up.

Drivers come in different styles. Some diodes need 5V to run, and wont work off a 3.7-4.2v lipo, so the boost driver was invented. It pumps the voltage up to 5V, and regulates the current. For 2 battery models that have a battery voltage of up to 8.4 volts, the buck driver was invented. What this guy does is uses the excess voltage and converts it into current.

Both types dispense heat while operating.

Some of our drivers are very simple, but perform the work needed.

Finally, a laser diode is NOT a LED but soon will be if you continue to use the resistor alone as your current regulator.

Or "i want to burn the arse hairs on my cat at 10 feet!":crackup:

tsteele93 said:

One of the best first questions I have seen so far. Usually we get, "where can I get a laser that will start my school on fire?" or "how many watts does it take to blind someone I don't like?"

Your question isn't stupid at all!

Also, different diodes require different voltages AND different currents. As a rule, the longer the wavelength, the lower the voltage. It will also depend on what kind of battery you want to use.

If you want to use two 3.7 v batteries to drive a red diode then you need a driver that can buck (decrease) the voltage in addition to supplying the correct current for the diode.

If you want to use a low voltage setup, lke two AA's at a total of 3v then you need a driver that can boost (increase) the voltage as well as provide the correct current for the diode.

Hang on, I'll get a post that explains it really well.

EDIT:.http://laserpointerforums.com/f67/f...river-tested-working-71433-8.html#post1033246

Click to expand...