DIY Homemade laser diode driver

[nikola tesla]

very useful calculator. isnt it nessesscary how much ampere the battery outputs?

 

[Fretwrecker94]

I found some potentiometers but i can't see anything about ohm.... only how much W, R and K...

If it says something like 1/2W 100K R
That means
W=Watts
K= multiply by 1,000
R=Resistance.... aka Ohms

Watts is just how much "power" can flow through it before it breaks, i believe

 

[Spyro]

so wats is not that much a deal? 1/4W is ok?

 

[Bluefan]

just build one, i actually bought 2 2ohm rezistors but they were 3.8 ohm XD what a luck
works preety well with my led'ed lazor diodes and my leds

Did you use a 4 wire measurement? If not, don't forget to compensate for the lead resistance which may explain the difference in measurement.

... resistor ...

fix'd

so wats is not that much a deal? 1/4W is ok?

If it smokes it's wrong. Calculate the maximum current from the power (P = I^2 * R) and don't exceed it.

 

[nikola tesla]

one question for me to understand: if i put two resistors parallel does their resistance and everything simply add up? like when I have two resistors of 3 Ohms and like 0.13 W does that make a total resistance of 6 Ohms and tolerance of 0.26 W ?

 

[Blord]

one question for me to understand: if i put two resistors parallel does their resistance and everything simply add up? like when I have two resistors of 3 Ohms and like 0.13 W does that make a total resistance of 6 Ohms and tolerance of 0.26 W ?

That is wrong. Resistors in series will add up Ohm.
Resistors in parallel will lower the total resistance and the total tolerance will be double in case you have two same resistors.

When there are only two resistors R1 and R2 in parallel this can be simplified to:

 

[rhd]

That is wrong. Resistors in series will add up Ohm.
Resistors in parallel will lower the total resistance and the total tolerance will be double in case you have two same resistors.

When there are only two resistors R1 and R2 in parallel this can be simplified to:

Technically, in both series and parallel, you should be doubling the total wattage, yes?

I mean, every resistor has a wattage of (basically) heat that it can dissipate. So every time you add a resistor (whether in series or parallel), that's another resistor to shoulder some wattage (heat) dissipation.

In series, that extra resistor adds resistance.
In parallel, that extra resistor lowered resistance.
In both cases, your effective wattage dissipation ability is higher.

So if you need a 5 ohm resistor capable of handling 2W, you could get that with:
- 1x 5ohm 2W resistor
- 2x 2.5ohm 1W resistor in series
- 2x 10ohm 1W resistor in parallel

Correct?

 

[Bluefan]

Correct, with equal resistances the power adds up. With unequal resistances the power isn't distributed evenly and one resistor reaches it's maximum sooner than the other.

 

[mals4938]

Okay so I am new this whole thing but either way I have come to the conclusion to power this 1w diode I have I will be setting my max mA at around 1700 now with the calculator supplied I am getting that I need .8 ohms and 2.00 watts so how do I set up the fixed resistors and what value should they be. Any help is much appreciated as said I am new to this bought the diodes cheap so it's whatever if they die. Oh and just a little info the LD is a 808nm 1W, datasheet says 1400mA to 2000 mA operating current and operating voltage is 2.1 to 3.

 

[mals4938]

Oh another question I got 4 diodes in my package 3 of which are 1W, but they did not mark which is the extra 100mW one is there anyway I can tell?

 

[rhd]

1) Don't double post. Edit your first post to add the extra info.

2) What kind of safety glasses do you have?

3) "I need .8 ohms and 2.00 watts so how do I set up the fixed resistors and what value should they be"
- What's your actual question, it sounds like you already know the answer ?

 

[mals4938]

Glasses are rated for 808nm and I cannot specify or say where I got them but on the other note, can I buy a .8 ohm resistor, as in what would I look for exactly and do I have to put 2 resistors in parallel or what?

EDIT: Never mind I found one I guess I was thinking to far into it thanks though. Oh and to explain myself I thought I would need to put 2 resistors in parallel to create a .8 ohm resistor.

 

[bloompyle]

Please edit your post and remove the quote, it's too long to quote simply for a few lines in response. Or edit it so only the content in question is being quoted.

 

[vkarbasi]

Hi and thank you for your kind and useful guide!

I wonder if I could ask you to give another links instead of these 2 ones below, because I coulden't open them and don't know what's the matter with them!

Daedal Lasers... NEW LOWER PRICES... LPF Coupon = LPF10OFF
________________________________
CLICK ME -- LASORB is now available for immediate purchase

thanks again :thanks:

 

[Tech_Junkie]

If you link a retail website in your signature you will be banned for spamming.

 

[GreenForce82]

Deleted by author