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# Minimum Volts For Burning?

#### Edi

##### New member
What is the minimum diode voltage required for burning things (like lighting a match, or popping a balloon)?

#### lasersbee

##### Well-known member
That's like asking how fast can a plane fly at 3 o'clock...
(not enough useful info)

1) Not all Laser Diodes are the same...
2) We don't know what lens you are using..

It requires Laser Beam wattage to burn things... not voltage...

Jerry

#### Edi

##### New member
OH, Sorry.

I kinda got confused. For some reason I thought the diode specs given are mV not mW :thinking: dunno where I came up with that.

So the current supplied to, let say, a 200mW will have to be more than a 100mW, (for like a 405nm diode and a decent lens) and have about the same voltage to burn.

Is there a general idea of how much watts would fry a 405nm 250mW diode? (that's what I have)

#### Things

##### New member
The current you feed the diode is in milliamps, the light output of the diode is rated in milliwatts. You have to put more milliamps into the diode to get 250mW out. For a 250mW diode, thats probably around 300mA. For a 405nm diode, you'd want around 4 volts.

Though like Jerry said, all diodes are different, so 300mA may be too much, or it might not even be a 250mW diode.

#### Edi

##### New member
The specs said it's 250mW but who knows how true that is.

Power is Volts times Amps, so if you put in 4V you only need about 62mA to get 250mW. That means the current has to be minimized to 62mA. Isn't that what the driver is for?

But the question still remains of what the lowest power is that you can burn with.

I know a 100mW will burn for sure if you put a good lens and set the power right but how about something lower like a 50mW or 30mW, will it still burn?

Just trying to get a general idea of how low i can get without losing the burning capability.

#### Bluefan

##### New member
A 250mW laser diode gives 250mW of light output. With a <100% efficiency you'll need to put in more than 250mW.
What do you consider burning capable? Getting smoke out of electrical table or vaporizing it?

#### blrock

##### New member
Even focused 30mW won't burn anything except maybe ultra thin black paper. You'd need at least 100mW to start melting thin plastic.
You'll really have to clarify "burn". 100mW will burn your skin if hold if you hold your hand long enough but it wont set wood on fire.
Bluefan was spot on. Their is a huge difference in "burning" electrical tape and burning wood to make a fire. There you'll need about 2000mW+.
FYI. My 10000mw laser sets wood on fire unfocused in about 3 seconds.

#### Edi

##### New member
Would the efficiency depend on each individual diode?

I mentioned in the very first post 'lighting a match or popping a balloon' and melting thin plastic would probably go under that as well. So 100mW would be minimum for all that?