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Help with capacitors and Battery voltage?

Platupus999

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Dec 5, 2020
Messages
42
Points
8
So i think i should add a capacitor to my laser in case of voltage spikes. However i really dont know which one i need. I am going to power a 50mw laser with lm317 (i also want to know what volatge should the battery be???). Will a 25v 10uF capcitor be appropriate???
 



Encap

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Joined
May 14, 2011
Messages
5,927
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First off : How old are you?
The nature and quality of your posts seem to indicate you are maybe 12yrs old or so and have no idea of what you are doing, why. and no money. LPF is not a babysitting forum that spoon feeds little kids with nothing to do and nobody to do it with answers they are too lazy to find themselves using the LPF search function and/or Google.
How much valuable time do you expect people to waste on whatever you want to do and don't know even the basics about how to do it especially on something that is going to be almost worthless when done?
Either you are very young or you are just trolling LPF with "help me" nonsense questions that have been answered hundreds of times over on LPF already, for attention--seems to be the case.
The Terms of Use of LPF that everyone must agree to, to become a member are as follow:
"3. Eligibility You must be the age of majority as that is defined in your jurisdiction to visit or use the Website in any manner. You represent and warrant to Laser Pointer Forums that You have reached the age of majority in your jurisdiction, and that You have the right, authority and capacity to agree to and abide by this Agreement. You also represent and warrant to Laser Pointer Forums that You will use the Website in a manner consistent with any and all applicable laws and regulations."
IN UK that means you are at least 18/an adult. See Terms of Use here: https://laserpointerforums.com/help/terms/

What is it that you want to do/build- the envisioned end product? As mentioned in one of your other threads "If you want see what you are getting into and save time and trouble, see what a 50mW 405nm is like--- you can get one on eBay UK for 5.66GBP including shipping, they are typically in the range of 50mW to 100mW-- luck of the draw as to what exact output is, see: https://www.ebay.co.uk/itm/10000m-4...sh=item5daedb68ce:g:li0AAOSwTr1ei~-y#shpCntId " You can take it apart to see what makes it tick if interested enough.

Do you even know maker and model/part number of the diode you say you have- saying 50mW 405nm means almost nothing--there are spec sheets for all diodes.
If you are just going to light up a bare diode with a driver and battery all that is going to happen is that you will destroy the diode due to thermal runaway - burn it out quickly. Without a proper lens the output will be just uncollimated bare diode output and a total waste of time doing.
If you are making a pointer you need a module for the laser diode, a lens, and heat sink, and a host to house everything including a li-ion battery or batteries needed not to mention again laser goggles.

As to your questions and to avoid dozens more of the same type and kind of questions being posted to LPF that you can easily find answers to --have a look at this thread, pretty much same song as yours. https://laserpointerforums.com/threads/help-building-lm317t-driver.62743/

And look at this excellent DTR thread: https://laserpointerforums.com/threads/laser-driver-it-can-be-done-rog8811.87507/
 
Last edited:

Platupus999

Member
Joined
Dec 5, 2020
Messages
42
Points
8
fi
First off : How old are you?
The nature and quality of your posts seem to indicate you are maybe 12yrs old or so and have no idea of what you are doing, why. and no money. LPF is not a babysitting forum that spoon feeds little kids with nothing to do and nobody to do it with answers they are too lazy to find themselves using the LPF search function and/or Google.
How much valuable time do you expect people to waste on whatever you want to do and don't know even the basics about how to do it especially on something that is going to be almost worthless when done?
Either you are very young or you are just trolling LPF with "help me" nonsense questions that have been answered hundreds of times over on LPF already, for attention--seems to be the case.
The Terms of Use of LPF that everyone must agree to, to become a member are as follow:
"3. Eligibility You must be the age of majority as that is defined in your jurisdiction to visit or use the Website in any manner. You represent and warrant to Laser Pointer Forums that You have reached the age of majority in your jurisdiction, and that You have the right, authority and capacity to agree to and abide by this Agreement. You also represent and warrant to Laser Pointer Forums that You will use the Website in a manner consistent with any and all applicable laws and regulations."
IN UK that means you are at least 18/an adult. See Terms of Use here:

What is it that you want to do/build- the envisioned end product? As mentioned in one of your other threads "If you want see what you are getting into and save time and trouble, see what a 50mW 405nm is like--- you can get one on eBay UK for 5.66GBP including shipping, they are typically in the range of 50mW to 100mW-- luck of the draw as to what exact output is, see: " You can take it apart to see what makes it tick if interested enough.

Do you even know maker and model/part number of the diode you say you have- saying 50mW 405nm means almost nothing--there are spec sheets for all diodes.
If you are just going to light up a bare diode with a driver and battery all that is going to happen is that you will destroy the diode due to thermal runaway - burn it out quickly. Without a proper lens the output will be just uncollimated bare diode output and a total waste of time doing.
If you are making a pointer you need a module for the laser diode, a lens, and heat sink, and a host to house everything including a li-ion battery or batteries needed not to mention again laser goggles.

As to your questions and to avoid dozens more of the same type and kind of questions being posted to LPF that you can easily find answers to --have a look at this thread, pretty much same song as yours.

And look at this excellent DTR thread:
fine then I will do it without your help!
 

Cyparagon

Well-known member
Joined
Sep 12, 2007
Messages
9,875
Points
113
Wae2sBG.png


Although it was rather harsh (even by my standards ) ;), there's some good info there. You would do well to read it.
 

Platupus999

Member
Joined
Dec 5, 2020
Messages
42
Points
8
First off : How old are you?
The nature and quality of your posts seem to indicate you are maybe 12yrs old or so and have no idea of what you are doing, why. and no money. LPF is not a babysitting forum that spoon feeds little kids with nothing to do and nobody to do it with answers they are too lazy to find themselves using the LPF search function and/or Google.
How much valuable time do you expect people to waste on whatever you want to do and don't know even the basics about how to do it especially on something that is going to be almost worthless when done?
Either you are very young or you are just trolling LPF with "help me" nonsense questions that have been answered hundreds of times over on LPF already, for attention--seems to be the case.
The Terms of Use of LPF that everyone must agree to, to become a member are as follow:
"3. Eligibility You must be the age of majority as that is defined in your jurisdiction to visit or use the Website in any manner. You represent and warrant to Laser Pointer Forums that You have reached the age of majority in your jurisdiction, and that You have the right, authority and capacity to agree to and abide by this Agreement. You also represent and warrant to Laser Pointer Forums that You will use the Website in a manner consistent with any and all applicable laws and regulations."
IN UK that means you are at least 18/an adult. See Terms of Use here:

What is it that you want to do/build- the envisioned end product? As mentioned in one of your other threads "If you want see what you are getting into and save time and trouble, see what a 50mW 405nm is like--- you can get one on eBay UK for 5.66GBP including shipping, they are typically in the range of 50mW to 100mW-- luck of the draw as to what exact output is, see: " You can take it apart to see what makes it tick if interested enough.

Do you even know maker and model/part number of the diode you say you have- saying 50mW 405nm means almost nothing--there are spec sheets for all diodes.
If you are just going to light up a bare diode with a driver and battery all that is going to happen is that you will destroy the diode due to thermal runaway - burn it out quickly. Without a proper lens the output will be just uncollimated bare diode output and a total waste of time doing.
If you are making a pointer you need a module for the laser diode, a lens, and heat sink, and a host to house everything including a li-ion battery or batteries needed not to mention again laser goggles.

As to your questions and to avoid dozens more of the same type and kind of questions being posted to LPF that you can easily find answers to --have a look at this thread, pretty much same song as yours.

And look at this excellent DTR thread:
Encap yes i do have a plan. I may be young (not 12 yrs old), i do have an idea of what i am doing! Before you say you need to be 18, has anyone ever actually complied with age limits online. Legal age to have an email is 13 i had one multiple years before that! By the way i dont care if i can barely see the beam, i will be happy in just knowing that i got it to work. If i fail once then i will learn for the next time how to do it better.

Parts i am using (feel free to complain):
  • 50mw 405nm laser diode (<75ma and 5v)
  • LM317 regulator
  • 5mw red laser module
  • 17 ohm resistor
  • 25v 10uF capacitor
  • 9v battery
  • 1N4001 Diode
  • Switch if i want one
Here is my steps (also feel free to moan at them):
1) dissamble the 5mw laser module, remove driver and diode leaving adjustable lense and metal casing
2) I have attached a diagram (i found it on this forum although i cannot remeber where), i will connect all the components like this using probably a breadboard initially and then i may solder them together. Obviously the values of the components are different and i am not using a potentiometer
3) once everything is assembled i will turn on the beam with a 9v battery as the power supply

AND YES I AM GOING TO USE LASER GOGGLES I HAVE ORDERED THEM FROM SURVIVAL LASER

Any problems with my plan, i would happily like to know :)

Anyway my question had nothing to do with that, i literallt just wanted to know what capacitor is appropriate. I have rarely used them and i just wanted a way of knowing how to calculate it


Is this good enough???
 

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WizardG

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May 9, 2011
Messages
909
Points
93
Is this good enough???

Well, except for 6V not being enough for this regulator and diode combination, and that if built on a breadboard it will likely destroy the diode, and the 4 ohm resistor not being a high enough value to provide a safety margin for the diode.........
 

Platupus999

Member
Joined
Dec 5, 2020
Messages
42
Points
8
Is this good enough???

Well, except for 6V not being enough for this regulator and diode combination, and that if built on a breadboard it will likely destroy the diode, and the 4 ohm resistor not being a high enough value to provide a safety margin for the diode.........
Did you not read what i said, i said the values of the components will be different! I said i was foing to use a 17ohm resistor and a 9v battery, read what i said. I said i was using the diagarm to help me connect everything up, not that i was gonna copy the diagram exactly!
 

Platupus999

Member
Joined
Dec 5, 2020
Messages
42
Points
8
Encap yes i do have a plan. I may be young (not 12 yrs old), i do have an idea of what i am doing! Before you say you need to be 18, has anyone ever actually complied with age limits online. Legal age to have an email is 13 i had one multiple years before that! By the way i dont care if i can barely see the beam, i will be happy in just knowing that i got it to work. If i fail once then i will learn for the next time how to do it better.

Parts i am using (feel free to complain):
  • 50mw 405nm laser diode (<75ma and 5v)
  • LM317 regulator
  • 5mw red laser module
  • 17 ohm resistor
  • 25v 10uF capacitor
  • 9v battery
  • 1N4001 Diode
  • Switch if i want one
Here is my steps (also feel free to moan at them):
1) dissamble the 5mw laser module, remove driver and diode leaving adjustable lense and metal casing
2) I have attached a diagram (i found it on this forum although i cannot remeber where), i will connect all the components like this using probably a breadboard initially and then i may solder them together. Obviously the values of the components are different and i am not using a potentiometer
3) once everything is assembled i will turn on the beam with a 9v battery as the power supply

AND YES I AM GOING TO USE LASER GOGGLES I HAVE ORDERED THEM FROM SURVIVAL LASER

Any problems with my plan, i would happily like to know :)

Anyway my question had nothing to do with that, i literallt just wanted to know what capacitor is appropriate. I have rarely used them and i just wanted a way of knowing how to calculate it


Is this good enough???
Just read the parts list...
 

Cyparagon

Well-known member
Joined
Sep 12, 2007
Messages
9,875
Points
113
It's close enough that if you wire everything properly, it will work. It just won't regulate properly because the voltage of the 9V battery will sag to under the minimum dropout of the regulator.

Either you use a higher current voltage source, or your driver is no better than a simple resistor.
 

Platupus999

Member
Joined
Dec 5, 2020
Messages
42
Points
8
Ok, thanks for the info
I thought that because the laser diode want 5v and the LM317 wanted 3v it would be ok
Ill use a 10v or 12v battery supply instead.
:)
 

Platupus999

Member
Joined
Dec 5, 2020
Messages
42
Points
8
Basically what they are saying is you gotta crawl before you can walk
Yeah im starting with a low power laser first, and the circuit i am using seems fine to me. I think Encap didnt realise i actually did have a plan, i do have a plan i just didn't show it. And WizardG didnt read my post correctly. My question was just about what capacitor is appropriate
 

Cyparagon

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Joined
Sep 12, 2007
Messages
9,875
Points
113
The capacitor should be on the output to help prevent oscillations. A low value ceramic capacitor is ideal, something in the range of 0.1µF would be fine - the value isn't critical.
 




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