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I need to wire a 2.2 volt laser diode and have no idea where to start help would be greatly appreciated.? Answered

I need to wire a 2.2 volt laser diode and have no idea where to start. I'm cheap and don't want to buy a driver and would like to build one myself.


The usual trick is to build a regulator which will supply the laser diode with constant current.    Such a gizmo is also called a constant current source.

Do not worry so much about voltage.  The voltage across a forward biased diode (in this case a laser diode) tends to be the same over a wide range of current.  I am guessing that the forward diode drop across your laser diode is about 2.2 volts.

The total power dissipated by your laser diode is the voltage across it multiplied by the current flowing through it, P= Iconstant*Vforward.  So, supposing you set your constant current regulator to deliver 10 mA.  Then Iconstant=10 mA, Vforward=2.2 V, and the total dissipated power is P= Iconstant*Vforward = (10 mA)*( 2.2 V) = 22 mW

You probably have some idea about the maximum amount of power dissipation your laser diode can withstand.  So choose a value for current that makes the power dissipation much smaller than this maximum value. 

I mean try getting it to work at a low power level first.  Also helpful for testing, is an ammeter, or a current sensing resistor you can measure the voltage across, in series with the laser diode. That way you can see at a glance the current flowing through the laser diode.


5 years ago

Penny wise and pound foolish.
Laser diodes are much more fragile in beginner's hands then LEDs.

Save the cost of a driver and loose the diode
Look at the wealth of Laser Diode instructables to learn how to avoid
destroying your device before it can harm your eyes.

Try starting with some of the ibles on the right side of this page.