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Voltage and diodes?

Hydrogen

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Do laser diodes give out more power from the move voltage you apply?
 

Cyparagon

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In a way, yes. It is more linearly a function of current though.
 

Hydrogen

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Ohh, I have an old rubbish red module from a Nintendo Wii gun, and I applied 3.4 volt and it was a bright dot, when I used 2AAA batteries, which it is supposed to run on , ity was dim?
 

anselm

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Hello and welcome to the forum!:wave:
Please take your time to read and understand what is being said here:
Laser driver - It can be done
It's the easiest and cheapest way you can safely power a laser diode.

Just directly connecting batteries to the laser diode is NOT recommended, you
can end up killing it very fast under most circumstances.;)
 

Hydrogen

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I wasnt talking about directly powering a LD with a battery, etc. That will let too much current flow in and blow it.

I meant can we mod laser power output by using higher voltages?
 

qumefox

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Not easily. the current draw of a diode vs the forward voltage aren't really linear. A diode being fed 3v might want to draw 500mA, but if you raise it to 3.1V, it's current draw could go up several hundred mA. This is why CC drivers are almost always used to drive laser diodes instead of CV sources. With just setting a voltage, it's really hard to dial in particular current levels. Very small changes in voltage will cause large changes in current.
 

Hydrogen

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So, if we had a very good quality variable voltage and current, then we could mod them?

Anyway in other words, is it better to use current rather than voltage to mod?
 

anselm

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is it better to use current rather than voltage to mod
Yes, very much so.
What is it that you want to "mod"(?), specifically?
 

Hydrogen

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Ohh, I was wondering if voltage modding rather that current modding would give you more performance of your laser.

Anyway, you only buy what you get.
 

Rafa

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If you put more voltage in your laser, with driver included two things can happen:
1.- You kill the driver (mostly with switching drivers)
2.- You kill the diode (mostly with bad quality chinese drivers)
 

Cyparagon

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Ohh, I was wondering if voltage modding rather that current modding would give you more performance of your laser.
Absolutely not. Output power is a roughly linear function of current, and current is a linear function of voltage (but with a very steep slope). So if you change the voltage, you're just changing the current in a more dangerous and imprecise way.

It can be done, but very small changes in voltage can lead to very large changes in current. Also, the diode draws less voltage as it heats up, and therefore draws more current, which can heat the diode faster - this is called thermal-runaway. If you've got a precise voltage-regulated power supply, it'll likely be capable of constant-current Anyway.
 




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