You must log in or register to reply here. Jan 13, Posts: Sign up using Facebook. Cheap, no battery to wear out, easy to use, goes anywhere, can’t break — especially useful for the right IR bands. I decided to try with a low current first just to be on the safe site but nothing happened.

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I’ll try out someone’s camera phone, too. Cheap, no battery to wear out, easy to use, goes anywhere, can’t break — especially useful for the right IR bands.

Help with LM laser driver | Laser Pointers

If you use a pot to make it variable like I did, make sure that you include an extra one ohm resistor in series with the pot so that you can’t make that value zero, it will always be the pot’s value plus one ohm. Post as a guest Name. I thought that you could either limit current or limit voltage, not both?

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But a clever trick is to look at it with your phone laseg camera. In his video [Afroman] describes how the LM can be used to regulate current rather than voltage to provide a constant current source under varying load.


Is a simple LM317-based laser diode driver safe for powering a laser diode?

Given a noisy input and a variable load, a voltage regulator will give a nice clean, stable output voltage. That helped but after a few days the radio failed again. By lasfr our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

If you have a regulated 5 volt supply, you can simply put a ohm, or slightly larger, resistor in series with it. This is not the case if I directly supply voltage from a battery without the LM in between.

The laser diode requires 7 mA and it will drop a maximum of 2. Sign up using Facebook. Again, multiplying for the current you finally get 2.

You will need 1W resistors, and heatsinks for the s. Connecting multiple current generators in parallel can be done and is done in many applications. The supply voltage is 5V measured 4.

Help with LM317 laser driver

Input voltage is pulled directly from the 5V line of the microUSB port. By using our website and services, you expressly agree to the placement of our performance, functionality and advertising cookies. Matrhis New member Mar 14, I realize that LMT is no good as of now. The LM is not a low-dropout type of linear regulator.


Since the resistor is 2. The current source uses a volt switch-mode power supply and the popular LM adjustable voltage regulator.

Email Required, but never shown. Is it safe for powering a laser diode?

Homemade Laser Driver with LM – Blog

I expect that regulator would do the right thing, and if it didn’t, that filter cap should cover the difference. Thank you for your interest in this question.

Joined Aug 25, Messages 5, Likes Points 0. Reading through the app note, the lmm317t response to changes in voltage is less than 10 usec and the deviation is small. Help with LM laser driver.

Further, the circuit is terribly inefficient consuming 6W to drive a 2.