I need a complete list for DIY Blu-Ray laser

[jonasa0601]

Xaser

But can't you just explain it to me? Cos i've read the page two times, and i cant figure it out.
I can easily solve Question 4, but can't 5.

Please list the things/terms used for DIY lasers.

 

[XaseR]

Bud, theres no real page I can put up and say 'these are laser equations', its all theory that has been dervied from phenomenon and applied to different situations i.e.lighting in your house, to your car battery, to your laser... there all linked with the same basic theory, you cant say that one has its unique special formulae, esp not for building your own laser driver. If you want to know then here I go, Ill try my best:

Ill give you my answer and type out a solution

Answer to q5: ~80ohms.

to work it out: V = IR, transpose this for R therefore: R = V/I , all the currents are given as mA (milli AMPS) BUT to make it easier convert it to Amps by dividing the mA by 1000 (also 10^3 or you can multiply by 10^-3, note: ^ means to the power). Then take the voltage and divide by the current to get the resistance.

Once you work it out for all, you will see its approx 80ohms.

Now if you look at q3 and q4, you will notice the pattern. The current is directly proportional to the voltage in any linear conductor at uniform temperature <-- ohms law. so in q4 when the resistance decreased to something like 200ohms, shows that it was not probably not a resistor. Because for a 50 volt increase at 500ohms (from q3) the current would be 0.1A or 100mA, directly proportional.

If you want an idea of how fundemental this is: Onboard merchant vessels, we still use pneumatic (air) controllers and actuators because the heat (more heat = more resistance for electrical componenets) from the engine room is enough to throw out the more sensitive electrical components. We use electrics to do a lot, but still make use of old fashioned air operated devices. It all really comes down to basic laws like ohms law.

God willing this makes sense.

 

[lasersbee]

[quote author=lasersbee link=1235928863/16#24 date=1236088101][quote author=nateh202 link=1235928863/16#20 date=1236032324][highlight]I had never soldered before yesterday and have a perfect laser today. [/highlight]Everyone here can help you, but you need to read up on stuff first. You can make a good phr laser for 80 dollars, and not much less. Trust me, it will be great for that price.

:-? :-? :-? :-? :-? :-?

Jerry[/quote]


We had some fun in PM's, Jerry  

Peace,
dave

[highlight]**EDIT**[/highlight]  and Nate handles frustration in a very mature manner.[/quote]
I'd imagine.... : Just saw this... ;D ;D ;D

Jerry

 

[charliebruce]

Has anyone used the water analogy to explain everything yet?

http://en.wikipedia.org/wiki/Hydraulic_analogy

Have a read through here and learn the concepts. It's not a scientific way by any means but it will help you get acquainted with the concepts of electronics. From there, you may want to buy a rapid prototyping board and some simple components, and just get used to working with electronics in reality. There are some very good "starter" projects you can do with discrete components, that you may find fun to build and be able to learn from. The more you practice the better you get...

Once you start using maths to describing your electronics work (and get it correct!), and fully understand voltage, current and resistance, then you will be better-prepared for anything this forum will throw at you. When you make the move from cheap and simple compnents to laser diodes, you should know that laser diodes don't follow some of the principles that many other components do, and that parts won't always operate in the ways they say they should. The best example of this is AC-DC wall adaptors - they may say that they are outputting 9V, but you shouldn't base your maths on this being correct! Also, you will find that an AC adapter will output a "dirty" voltage, meaning it will fluctuate as it runs, and so needs a capacitor to "smooth" these harmful spikes. I suspect that once you're at this level of thinking, you will come back to this thread and realise just how much you've learnt. That will be when you're ready to build a laser for yourself.

Remember that we can tell you all the facts and figures about the lasers and drivers, but unless you understand them and can learn and use the knowledge we give you, there's no benefit whatsoever.

 

[lasersbee]

I got the point, but not totally..

But i just want to know enough to make my own laser.

Can someone just tell me which basic things i need to know before making a laser?
I already know Amp, Current, and learning resistance right now..

I can't solve the 5th question here:

http://www.facstaff.bucknell.edu/mastascu/elessonshtml/EEIndex.html <--- Elements : Resistors and then scroll down
Can anyone help me?

I just looked at question #5... and I have a problem with it...

It says.....

P5.   The data below are all taken from measurements of the same resistor.  
What is the value of the resistance?

                                    Voltage (v)   Current (ma)                   My Calcs (R=V/A)

                                        0.95                12.0                           79.1666 ohms
                                        2.03                24.8                           81.8548 ohms
                                        2.99                37.1                           80.5929 ohms
                                        5.11                60.0                           85.1666 ohms

Then to get 100% on the Test... their answer is 83 Ohms.... :-? :-? :-?
Have I missed something or are their values in error... :-?

Jerry

 

[XaseR]

Hey charlie. Yeah a few posts back "Think of it as PRESSURE in a water pipe, when you loose that pressure THATS IT MATE you've had it, your not going to have any flowing water. So the voltage allows the current to flow, thats it." It is a good way to describe the voltage.

The voltage that you see comming out from the 'wall', your 9V, is exactly what you use for calculations... its the Root Mean Squared value, and that is the appropriate heating effect of the AC circuit compared to its DC equivalent. And to work that out : Vrms = Vpeak / root2 or Vpeak = Vrms x root2
You wouldnt really ever work with peak values, the RMS is what is used for majority of calculations.

Also about AC rectification, majority of adaptors (apart from some ancient ones, so were not talking about common laptop adapters here) do come with capacitors, its called 'capacitor smoothing' and thats used after the 'bridge rectifying'.

Edit: Yeah Jerry, hehe, thats what I got. Not sure why its 83. The mean of all the answers isnt even 83.

Edit 2: Take the average of all the Volts, Take the average of all the currents, Find out the final resistance = 82.7, round it up to 83. Thats where they've got it!

 

[charliebruce]

I tried that too, and you're right, those values you listed should be correct. Their marking page wants 83 ohms. I'd avoid relying on that site for any accurate info, if they can't handle V=IR then what hope is there? ;D

 

[XaseR]

Idd. I think there after an average anyway.

 

[jonasa0601]

Okay, i'll read on your last post tomorrow, and i'll maybe get some "starter" items i can play around with to get it in praxis.

I get the q5 now, i just couldn't figure out that i should make it amps

(Stupid me..)

Well, i didn't really thourd that i should learn more than calculate ohm(put on resistor), choose the right voltage and the right current.. but maybe there's more than that for simple circuits and drivers..

 

[XaseR]

Hehe Buddy theres WORLDS more! It is exciting when you get into it. Ive started 6.6kV or 6600V (thats ~9300V peak ac) motor and steam generators at work, it is good!

 

[lasersbee]

Edit: Yeah Jerry, hehe, thats what I got.  Not sure why its 83.  The mean of all the answers isnt even 83.

Edit 2: Take the average of all the Volts, Take the average of all the currents, Find out the final resistance = 82.7, round it up to 83.  Thats where they've got it!

I can see the logic at getting to 83  Ohms... But they use Fractional values for Volts and Current...
then round up the calculated Resistance value... :-?

It is extremely confusing to the New Members who want to learn the Basics... when simple equations
don't add up...

The question #5 should have been phrased a little clearer...  since the previous questions
dealt with exact calculations...

@jonasa0601... I see that you ARE reading... that is a great start... [smiley=thumbsup.gif]


Jerry

 

[Bionic-Badger]

Those "fractional volts" reminds me of an old joke about the difference between mathematicians, (physical) scientist, and engineers, which goes something like this:

A mathematician, physical scientist, and engineer were all asked: "What is pi?"

Mathematician: "The ratio between the circumference of a circle and its diameter."

Scientist: "How many significant digits? To five, it's 3.1416."

Engineer: "About three."

 

[jonasa0601]

On the same page as before theres some more questions longer down.. something with colors on resistors, and i don't get it.. I've read it twice but can someone explain it to me?

 

[spaceman_hux]

50 dollars is very ambitious
you may be looking at 100 dollars

 

[Bionic-Badger]

On the same page as before theres some more questions longer down.. something with colors on resistors, and i don't get it.. I've read it twice but can someone explain it to me?

This clearly shows a serious lack of effort.  The whole resistor color section is RIGHT ABOVE the question.  Furthermore, how hard is it to search for "resistor colors" on google and find a website on the exact topic, with a damn Javascript resistor calculator to boot (hint: it's the first link)? Then you can experiment with various values and see for yourself how things work. I remember never bothering to memorize the color codes or their meanings, and just plugged the colors into a calculator like that.  Take some initiative for once.

These are the most basic fundamentals of electronics.  But even more fundamental is the ability to find and decipher information on your own, without having people hold your hand.  If this is too much for you, you shouldn't be making high-powered lasers.  Come back when you have some problem solving maturity.

 

[XaseR]

[quote author=jonasa0601 link=1235928863/32#44 date=1236233725]On the same page as before theres some more questions longer down.. something with colors on resistors, and i don't get it.. I've read it twice but can someone explain it to me?

This clearly shows a serious lack of effort. The whole resistor color section is RIGHT ABOVE the question. Furthermore, how hard is it to search for "resistor colors" on google and find a website on the exact topic, with a damn Javascript resistor calculator to boot (hint: it's the first link)? Then you can experiment with various values and see for yourself how things work. I remember never bothering to memorize the color codes or their meanings, and just plugged the colors into a calculator like that. Take some initiative for once.

These are the most basic fundamentals of electronics. But even more fundamental is the ability to find and decipher information on your own, without having people hold your hand. If this is too much for you, you shouldn't be making high-powered lasers. Come back when you have some problem solving maturity.[/quote]

Im glad you said it, I didnt have the heart too!!