Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers





Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes
Laser Technology Laser Pointer Parts Lasers by Wavelength
Top 10 Laser Pointer Companies Laser Pointer Company Database Visible Beam Laser Pointers


One laser store meets all your needs

























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Tutorials, Help & Repairs



LPF List of Laser Pointer Companies (link opens new window)



Reply
 
LinkBack Thread Tools Display Modes
Old 09-04-2008, 06:49 PM #1
WackBag's Avatar
Class 2 Laser
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
WackBag WackBag is offline
Class 2 Laser
WackBag's Avatar
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
Default Flexdrive output issue

I have a flexdrive hooked up to 3 x AAA batteries. For a dummy load I have 4 x 1n4001 diodes and a 1/2 watt 1K Ohm resister. With the dummy load connected, I get about 7 volts off the diode side of the PCB. When connected between the diodes I get about 2.55 v's. When I check for current on either side of the resister I can only get a max of approx 270 mV. The 270 mV is achieved by turning the pot. The range is about 115 - 270 mV. I would like to p0wer an open can diode (red) at about 420 mV. Why am I not able to achieve this from the flexdrive? What am I missing? Thanks in advance.
Alan


WackBag is offline   Reply With Quote







LPF List of Laser Pointer Companies (link opens new window)







Old 09-04-2008, 07:04 PM #2
Class 2 Laser
 
Join Date: Jul 2008
Posts: 281
Rep Power: 12
ArRaY will become famous soon enoughArRaY will become famous soon enough
ArRaY ArRaY is offline
Class 2 Laser
 
Join Date: Jul 2008
Posts: 281
Rep Power: 12
ArRaY will become famous soon enoughArRaY will become famous soon enough
Default Re: Flexdrive output issue

Keep in mind that you measure across a 1k ohm resistor, not a 1 ohm one.
I=U/R. Also, you gotta measure the voltage across the resistor.
Couldnīt see from you post what you where measuring b/c you seem to be mixing up mV and mA...

ArRaY
ArRaY is offline   Reply With Quote
Old 09-04-2008, 07:31 PM #3
WackBag's Avatar
Class 2 Laser
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
WackBag WackBag is offline
Class 2 Laser
WackBag's Avatar
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
Default Re: Flexdrive output issue

Sry...I should have said mA. I am placing the MM's leads on each side of the resistor. + on the + side and - on the 1n4001 diode side which leads to the - side of the PCB. My dummy load is 4 x 1n4001 diodes in line with the resistor.
WackBag is offline   Reply With Quote
Old 09-04-2008, 09:01 PM #4
HumanSymphony's Avatar
Half Afro / Half Man
 
Join Date: May 2008
Location: Washington
Posts: 2,031
Rep Power: 216
HumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond repute
Send a message via AIM to HumanSymphony Send a message via MSN to HumanSymphony Send a message via Yahoo to HumanSymphony
HumanSymphony HumanSymphony is offline
Half Afro / Half Man
HumanSymphony's Avatar
 
Join Date: May 2008
Location: Washington
Posts: 2,031
Rep Power: 216
HumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond reputeHumanSymphony has a reputation beyond repute
Send a message via AIM to HumanSymphony Send a message via MSN to HumanSymphony Send a message via Yahoo to HumanSymphony
Default Re: Flexdrive output issue

Quote:
Originally Posted by ArRaY
Keep in mind that you measure across a 1k ohm resistor, not a 1 ohm one.
I=U/R. Also, you gotta measure the voltage across the resistor.
Couldnīt see from you post what you where measuring b/c you seem to be mixing up mV and mA...

ArRaY
with what he's doing, the mV will equal the mA 1:1
__________________
Quote:
Originally Posted by yobresal View Post
I didn't even know there was a game.
Quote:
Originally Posted by Gryphon View Post
LOL, i didn't know there was a movie
Quote:
Originally Posted by HumanSymphony View Post
DOUBLE LOL!
Laser Rap (Part I)
Laser Rap (Part II)
Laser Rap (Part III)
HumanSymphony is offline   Reply With Quote
Old 09-05-2008, 01:40 AM #5
WackBag's Avatar
Class 2 Laser
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
WackBag WackBag is offline
Class 2 Laser
WackBag's Avatar
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
Default Re: Flexdrive output issue

Does anyone else have an idea? I switched out the flexdrive and got the same result. Are the standard AAA's just not putting out enough juice. These are just standard radio shack alkalines. I measured 4.6v's coming direct from the flashlight body to the flexdrive. i replaced the batteries with brand new and was able to get 300 mA's from the output of the flexdrive. Anyone else know the issue?
WackBag is offline   Reply With Quote
Old 09-05-2008, 03:54 AM #6
rkcstr's Avatar
Class 3R Laser
 
Join Date: Dec 2007
Posts: 1,368
Rep Power: 142
rkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond repute
rkcstr rkcstr is offline
Class 3R Laser
rkcstr's Avatar
 
Join Date: Dec 2007
Posts: 1,368
Rep Power: 142
rkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond repute
Default Re: Flexdrive output issue

I think you're using a MUCH too large resistor on there and willing to bet that it is why you're getting strange readings. 270mV through a 1Kohm resistor means the driver's only putting out 0.27mA (Ohm's Law, V = I / R), probably because to push 500mA through 1Kohm would require 500V from the driver!

Try finding a smaller resistor to put in series... 1ohm is easiest, since it would be 1mV = 1mA, but you could use like a 10ohm or whatever that's relatively low resistance and use that pesky Ohm's Law yourself.
__________________
Laser drivers and Test Loads - rkcstr.com

Enter discount code "LPF" during checkout to save 10% off of the regular prices!
rkcstr is offline   Reply With Quote
Old 09-05-2008, 04:31 AM #7
jayrob's Avatar
Class 4 Laser
 
Join Date: Sep 2007
Location: Northern CA, U.S. Astrophotography! (Some of my Photos)
Posts: 9,851
Rep Power: 3922
jayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond repute
jayrob jayrob is online now
Class 4 Laser
jayrob's Avatar
 
Join Date: Sep 2007
Location: Northern CA, U.S. Astrophotography! (Some of my Photos)
Posts: 9,851
Rep Power: 3922
jayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond reputejayrob has a reputation beyond repute
Default Re: Flexdrive output issue

Here's a good diagram for setting up a 'dummy load' from rog8811. This shows a DDL driver, but it is the same for a FlexDrive.
http://www.laserpointerforums.com/fo...m=1197651171#1

As far as your question on the AAA batteries, as long as you have them connected properly (in series), there should be at least 4.5 volts. Perfect for the FlexDrive.

The new FlexDrives have two settings as well. Look at the picture showing the 'high range jumper' in the instruction sheet:
http://hacylon.case.edu/laser/lavadr...nual_%20V2.pdf

But rkcstr is correct, you need a 1 ohm resistor... not a 1K ohm. (Or, no resistor at all. Just use mA's setting on your DMM instead of mV)
Jay
__________________
Personal lasers:
(just a few - too many to list) RPL 425, Sypder III Krypton, RPL 35 (473), GLP-473, GLP-593.5, HeNe 632.8,
Many DIY 445, red, blu-ray, green, 635, and 450 builds...


Looking for a DIY kit?


Take a look at some of my more popular kits linked in color...

* FS: 405-G-1 Glass Lens Mod for Blu-ray! 31% increase in power vs AixiZ acrylic!

* FS: New! 1000 Lumen XML-2 Maglite Modification With Voltage Monitor! - Parts or Complete Light! Must see!

* FS: Polished Stainless Steel Green Kit! Easy assembly in minutes!

* FS: Large Maglite Monster Kits! Side Button Forward Clicky! Custom Head Option! Gnarly...


Click here for a list of my build kits! Projects and tutorials too!

jayrob is online now   Reply With Quote
Old 09-05-2008, 05:00 AM #8
Ryo Ryo is offline
Class 1M Laser
 
Join Date: Aug 2008
Posts: 134
Rep Power: 10
Ryo is on a distinguished road
Ryo Ryo is offline
Class 1M Laser
 
Join Date: Aug 2008
Posts: 134
Rep Power: 10
Ryo is on a distinguished road
Default Re: Flexdrive output issue

Quote:
Originally Posted by HumanSymphony
[quote author=ArRaY link=1220554179/0#1 date=1220555058]Keep in mind that you measure across a 1k ohm resistor, not a 1 ohm one.
I=U/R. Also, you gotta measure the voltage across the resistor.
Couldnīt see from you post what you where measuring b/c you seem to be mixing up mV and mA...

ArRaY
with what he's doing, the mV will equal the mA 1:1[/quote]

Only if your talking about using the 1 Ohm load.

Definitely change it to 1 Ohm. I use 1 Ohm 1watt rated resistor.

Also there's 2 settings in the FlexDrive. One is low which start at 60 mA to (I think) 110mA. Then there's the location to jumper which puts you in the high power side.. which brings it up to somewhere in the 400 mA range (if I remember correctly). Look at his instructions on what to jumper.
__________________
Laser Built:
Red 150 mW Burner Laser
Violet (blu-ray) 10 mW Laser
Ryo is offline   Reply With Quote
Old 09-06-2008, 09:47 PM #9
WackBag's Avatar
Class 2 Laser
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
WackBag WackBag is offline
Class 2 Laser
WackBag's Avatar
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
Default Re: Flexdrive output issue

Ok...I feel really stupid and I'll tell you why in a second. First though Jay sent me a 3 ohm 1 watt resistor with his heatsink. I replaced the 1K ohm resistor with the 3 ohm in my dummy load. Do I now need to multiply the mA shown on my MM by 3 to get the true current? For example, I was able to tune the pot for 140 mA with the 3 ohm resistor, do I then multiply the 140 x 3 to get the results without the resistor? Meaning when I hook up the LD it will be receiving 420 mA of current? If this is true then the mistake cost me 2 open can red diodes. With the 1K Ohm resistor I was turning the pot till it maxed out, with the 3 AAA batteries that was about 270mA and with 2 CR-123 I was able to get the driver to put out about 390 mA. When I connected the LD...I'm guessing they fried because I was giving it like a gazzillion mA's. That explains why the 2R7 on the flexdrive was too hot to touch Let me know...but so far this has cost me about 60 bucks...flush gurgle gurgle
WackBag is offline   Reply With Quote
Old 09-06-2008, 10:01 PM #10
Class 2 Laser
 
Join Date: Jul 2008
Posts: 281
Rep Power: 12
ArRaY will become famous soon enoughArRaY will become famous soon enough
ArRaY ArRaY is offline
Class 2 Laser
 
Join Date: Jul 2008
Posts: 281
Rep Power: 12
ArRaY will become famous soon enoughArRaY will become famous soon enough
Default Re: Flexdrive output issue

Let me re-state, that the formula is I=U/R. That means, if you use a 3 ohm resistor, you get I=V/3.
Using your values, you can solve it. I=140/3 = 46,66666.....

Again, it is not clear what you are measuring and what scale you are using.
If you want to measure the current going into your diode, you have 2 possibilities.

First, you could measure the _Voltage_ _across_ the 3 ohm resistor, using the mV or V scale on you meter, and then calculate the mA,
or you could measure the current directly with your meter. You would then have to create a break in the electrical path, and brigde that break with your meter, set to mA or A scale. However, this will not always be the best option, as you need to create the break and many/most DMMīs(right?) are only fused to about 200mA.Unless youīre not using the 2A option, but I donīt know its accuracy.

ArRaY
ArRaY is offline   Reply With Quote
Old 09-06-2008, 10:18 PM #11
WackBag's Avatar
Class 2 Laser
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
WackBag WackBag is offline
Class 2 Laser
WackBag's Avatar
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
Default Re: Flexdrive output issue

I don't follow the logic. *Isn't the resistor providing 3 ohm's of resistance, so if I am measuring the current going across the 3 ohm resistor using the mA setting on my MM and get 140 mA's then the current going to the LD without the resistor would be 3 times that or 420 mA's? *In other word's, if I was using a 1 ohm resistor then 1 mA = 1 mV. *So since I am using a 3 ohm resistor then I need to multiply my result by 3 versus dividing? *I'm thinking if I removed the 3 ohm resistor then I would be getting 3 times the current? I look at the formula this way...V=IR. So the Volts in Mv=140mA x 3 ohms.
WackBag is offline   Reply With Quote
Old 09-06-2008, 10:42 PM #12
Class 2 Laser
 
Join Date: Jul 2008
Posts: 281
Rep Power: 12
ArRaY will become famous soon enoughArRaY will become famous soon enough
ArRaY ArRaY is offline
Class 2 Laser
 
Join Date: Jul 2008
Posts: 281
Rep Power: 12
ArRaY will become famous soon enoughArRaY will become famous soon enough
Default Re: Flexdrive output issue

Forgot to say, if your going to measure current directly, you have to measure it without the resistor.
It is there in the first place, to eliminate the need to create a break in the circuitry, to measure mA as you can measure mV across it and then calculate the current.

ArRaY
ArRaY is offline   Reply With Quote
Old 09-06-2008, 11:21 PM #13
WackBag's Avatar
Class 2 Laser
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
WackBag WackBag is offline
Class 2 Laser
WackBag's Avatar
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
Default Re: Flexdrive output issue

So is my logic correct?
WackBag is offline   Reply With Quote
Old 09-07-2008, 12:36 AM #14
rkcstr's Avatar
Class 3R Laser
 
Join Date: Dec 2007
Posts: 1,368
Rep Power: 142
rkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond repute
rkcstr rkcstr is offline
Class 3R Laser
rkcstr's Avatar
 
Join Date: Dec 2007
Posts: 1,368
Rep Power: 142
rkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond repute
Default Re: Flexdrive output issue

[s]OK... first, do you have DrLava's Flexdrive or my Micro-Drive? *You mentioned a 2.7ohm resistor, which mine has, but I don't know about the Flexdrive?[/s]

Anyway, I think you have some misconceptions about all of this.

First, current is the flow of electrons (electricity), while voltage is the electrical potential. *You can measure the voltage, similar to air pressure or water pressure, with an external source, like a gauge or for electricity, a voltmeter. *BUT, to measure flow, its basically the "volume" of eletrons passing any point in a given amount of time... you can only measure that by flowing electrons through the instrument. *So, if you just put an ammeter (ie multimeter set to A or mA) in parallel (connected across) a resistor, the meter's internal resistance is going to act as a parallel resistor and share the current with the resistor, not giving the full current to the meter. *You need ONLY the meter in line with the current to measure it fully.

The reason we say to measure the VOLTAGE across a resistor is because if you measure the voltage across a resistor of a known resistance, by Ohm's Law (already quoted here multiple times over), you can calculate current. *So, if you have your 3 ohm resistor, and you measure the voltage across it, you can calculate current as follows (for example):

V = I * R
V / R = I
I = 0.15V / 3ohms
I = 0.050A = 50mA

EDIT: *Nevermind about the question about the flexdrive... I see now you were talking about the inductor on there... its 2.7uH, lol. *It's not a resistor, but a coil of wire wound around a ferrous core.
__________________
Laser drivers and Test Loads - rkcstr.com

Enter discount code "LPF" during checkout to save 10% off of the regular prices!
rkcstr is offline   Reply With Quote
Old 09-07-2008, 01:18 AM #15
WackBag's Avatar
Class 2 Laser
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
WackBag WackBag is offline
Class 2 Laser
WackBag's Avatar
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
Default Re: Flexdrive output issue

Well a picture is worth a thousand words...and sorry to be a pita but I'm still confused. I'll post 3 pictures.
This is my DMM set to mA and it is reading 139mA with the leads across the 3 ohm resistor. If I want to drive an open can red diode at 420mA, what should I be reading in my DMM???
Attached Thumbnails
Flexdrive output issue-cimg0603.jpg  
WackBag is offline   Reply With Quote
Old 09-07-2008, 01:18 AM #16
WackBag's Avatar
Class 2 Laser
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
WackBag WackBag is offline
Class 2 Laser
WackBag's Avatar
 
Join Date: Aug 2008
Location: Alabama
Posts: 387
Rep Power: 11
WackBag will become famous soon enoughWackBag will become famous soon enough
Default Re: Flexdrive output issue

Picture showing close up view of dummy load.
Attached Thumbnails
Flexdrive output issue-cimg0604.jpg  
WackBag is offline   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 04:00 AM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC