i have a 3B class laser that i got it from a dvd rw ... i use the circuit below to power it ... it supposed to work at 250 mA and 562.5 mW but when i turn it on it seems that it doesn't work as it supposed to ..
the beam is so weak ... i don't know .. maybe the laser is IR laser ... but the problem is even if i focus the beam it still doesn't burn any thing ... i saw many projects in the enternet that use it as a burner but mine doesn't work ..

so can you tell me what is the problem and how to solve it !?

 

Would it be possible to measure the current and voltage that the diode operates at?

 

Would it be possible to measure the current and voltage that the diode operates at?

The voltage is 2.25 v
i can't measure the current now

 

Hello,

What happens when you raise the input voltage?
Keep in mind that you will have a voltage drop of almost 2 Volts accross the LM and 1.2 Volts accross the resistor.



Bertus

 

http://www.lasersafetyfacts.com/3B/

Please read the above article BEFORE you continue, then decide if you should stop. You cannot regain your sight after damage from lasers and your world will become a dark place.

 

Aside from those VERY REAL DANGERS that come with an invisible beam laser is the probability that the laser is not capable of that kind of power level. A half watt laser does need a heat sink to avoid getting way too hot quite rapidly. If you have no convenient means of measuring current then put a 1000 ohm resistor in series and read the voltage across the resistor, you will get 1 millivolt per milliamp through the resistor.

In addition, you also need to make sure that you have the polarity of the applied voltage correct.