The first pushes serial data to a mySQL database. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of service , privacy policy and cookie policy , and that your continued use of the website is subject to these policies. Deleted member Guest Apr 30, I built a driver that combines both, using 2 LM’s, the first configured as a variable voltage regulator to feed the one configured as a current regulator, which is also set up as variable. High schooler [Vlad] spent about a year building up his battery-operated, wireless weather station.

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That large uF capacitor will pull down the right side of the sense resistors to close to zero. One of our favorites is pulling the stock linear regulator in favor of a switch mode regulator. I am using an LMT to provide constant current to my laser diode. Fri Jan 13, 8: Simple constant current regulator for a 1.

I don’t get a clear pulse waveform and it seems very noisy.

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

I didn’t understand shunt resistors much back then. This can over-current your diode and burn it out which they do quite easily, I may add. The circuit of the Laser Driver: My intent is to build a simple driver for a laser Kaser with an operating voltage of 4. But isn’t the LM regulator taking care of that itself already?


The discussion just reminded me of anti-Stokes phosphors. Can I use multiple of them laesr parallel like this, or should I completely scrap this schematic? Any other regulator with a low noise and low drop out voltage By using paser site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

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I’ve built several LM based drivers for my lasers over the years. Also, lm317f this circuit actually works, how can I calculate the power loss on the LM regulators? I decided to try with a low current first just to be on the safe site but nothing happened. Most of those jobs were for one-off precision measurements or even to drive a string of LEDs in what he describes as a pair of migraine-inducing glasses.

At that kind of power level, you also don’t want to depend on current alone – you should be monitoring the output optical power and regulating it to a safe level. Mon Jan 16, 1: I thought that you could either limit current or limit voltage, not both?

Help with LM317 laser driver

I realize that LMT is no good as of now. I think you need to look into a safer laser driver.


I don’t know much about laser diodes though, so I am not sure what sort of sensitivity they have to any of that. The attached datasheet has a set of curves on page 7 called “dropout voltage” that illustrates this point: I built a driver that combines both, using 2 LM’s, the first configured as a variable voltage regulator to feed the one configured as a current regulator.

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.

Help with LM laser driver | Laser Pointers

There is one for voltage, and one for current depending on the way you wire the circuit. If not why have both?

Constant current doesn’t mean constant output laeer the laser. The laser diode requires 7 mA and it will drop a maximum of 2. The circuit you designed is fine. I want to drive a laser diode with constant current and aim it at a photodiode, then using a transimpedence amplifier I will monitor any changes in light intensity.

Would be fine with a laser, I think.