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Laser ohm resistor project question Answered

So I am doing a big modifiction of Kipkay's burning laser project. I am making it into a gun, and the only resistor I can find is a 4.7. Will that do? I have a 5mw module like his, and a 250mw 650nm laser diode. Also I am going to use two C-batteries, so its 12volts total. 

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Plasmana

8 years ago

I assume you are talking about this 'ible Laser Flashlight Hack!!?

And you need a 1 ohm resistor for this laser driver?

You can put four 4.7 ohm resistors in parallel to get approxmantly 1 ohm.

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thedonquixoticPlasmana

Reply 8 years ago

Not exactly, I didn't use a laser drive, instead I just bought a diode on Ebay so I could be certain of the mw.

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gmoon

8 years ago

Try an amplifier parts store like Hoffman Amps, (look for 1 ohm, 1% in the resistor section) or the larger parts houses like mouser.

You're measuring the voltage drop across a 1 ohm resistor. Thanks to good old "Ohms Law", the millivolts dropped over 1 ohm equals the milliamps, 'cause 1 ohm is the denominator (current = E/R, or E/1 in this case). That's exactly how tube amp builders measure the current draw of power tubes...

Because this is a precision measurement, you should use a 1 ohm, 1% tolerance resistor. And an accurate meter... 1 watt rating is fine.

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thedonquixoticgmoon

Reply 8 years ago

Hey thanks Gmoon. I know that this reply is a little late but I got swamped by some work.

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gmoongmoon

Reply 8 years ago

Sorry, that Hoffman link doesn't work; I guess everyone gets a ID cart automatically...

Try a general link to the site, and click on the web store...