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 > Drivers, Test-load, Power Supply, & Batteries



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



Reply
 
LinkBack Thread Tools Display Modes
Old 05-12-2014, 01:49 AM #1
Junior Member
 
Join Date: May 2014
Posts: 3
Rep Power: 0
cutechi is on a distinguished road
cutechi cutechi is offline
Junior Member
 
Join Date: May 2014
Posts: 3
Rep Power: 0
cutechi is on a distinguished road
Default FlexMod bias current can not go down to 0

Hi there,

I got a flexmod and 2W 445nm, I can successfully switch the laser on/off by sending TTL signals (0/5V), but I can not set the standby bias current to 0. I turned the bias pot to the minimum, but i still read around 15ma, any advice or test i can do? Thanks!


cutechi is offline   Reply With Quote







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







Old 05-12-2014, 03:42 AM #2
djQUAN's Avatar
Class 3R Laser
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
djQUAN djQUAN is offline
Class 3R Laser
djQUAN's Avatar
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
Default Re: FlexMod bias current can not go down to 0

TTL inputs usually control the current going into the diode. But not the circuitry of the driver. You will have to use a switch on the driver inputs.
djQUAN is offline   Reply With Quote
Old 05-12-2014, 03:53 AM #3
Junior Member
 
Join Date: May 2014
Posts: 3
Rep Power: 0
cutechi is on a distinguished road
cutechi cutechi is offline
Junior Member
 
Join Date: May 2014
Posts: 3
Rep Power: 0
cutechi is on a distinguished road
Default Re: FlexMod bias current can not go down to 0

Quote:
Originally Posted by djQUAN View Post
TTL inputs usually control the current going into the diode. But not the circuitry of the driver. You will have to use a switch on the driver inputs.
Hi, djQUAN

Thanks for your answer, but I'm afraid i didn't quite get your point, what switch you are referring to?

Sorry I missed one piece of information in the previous post, I basically shorted the modulation input to ground, which for sure is 0V, but I still read 15ma current.

I think your answer is giving me hints, but could you elaborate more? Thanks!
cutechi is offline   Reply With Quote
Old 05-12-2014, 05:04 AM #4
Cyparagon's Avatar
Class 4 Laser
 
Join Date: Sep 2007
Location: Wisconsin
Posts: 9,142
Rep Power: 9321
Cyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond repute
Cyparagon Cyparagon is online now
Class 4 Laser
Cyparagon's Avatar
 
Join Date: Sep 2007
Location: Wisconsin
Posts: 9,142
Rep Power: 9321
Cyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond repute
Default Re: FlexMod bias current can not go down to 0

15mA into the driver, or 15mA out of the driver?
__________________
A problem well stated is a problem half solved.
Cyparagon is online now   Reply With Quote
Old 05-12-2014, 07:15 AM #5
djQUAN's Avatar
Class 3R Laser
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
djQUAN djQUAN is offline
Class 3R Laser
djQUAN's Avatar
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
Default Re: FlexMod bias current can not go down to 0

The driver circuitry is always on if you apply power no matter how you mess with the modulation input. The modulation input just controls the amount of current going out of the driver.

So if you set the modulation to zero, your output is zero but the driver circuitry remains operating, waiting for the modulation to change.

You will need a switch for the power input to disconnect the whole thing from the battery to get zero quiescent current draw if you want totally no current consumption when off.
djQUAN is offline   Reply With Quote
Old 05-12-2014, 09:56 AM #6
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: FlexMod bias current can not go down to 0

Is it a Flexmod P3 ? ,

The idea is to use the bias pot to set the current to the diode threshold and then the TTL input will take the current from bias set to maximum set diode current

Is there a main reason you need the bias current to be zero , 15ma is quite below the lasing threshold of the 445nm diodes assuming its 15ma though the diode and not just the driver circuit itself pulling current ( more likely the diode is getting the 15ma )

For you the only way to stop this is to remove power fully from the flexmod .
__________________
Stuck In The places I Hated The Most , Reboot My Memory , Restart My heart , Seal Up All Of My Wounds Take Me Back To The Start !
Rip Me To Peices , Replace What You Can , Bury The Rest And Build A New Me To Plan !

Last edited by DashApple; 05-12-2014 at 01:41 PM.
DashApple is online now   Reply With Quote
Old 05-12-2014, 01:39 PM #7
Junior Member
 
Join Date: May 2014
Posts: 3
Rep Power: 0
cutechi is on a distinguished road
cutechi cutechi is offline
Junior Member
 
Join Date: May 2014
Posts: 3
Rep Power: 0
cutechi is on a distinguished road
Default Re: FlexMod bias current can not go down to 0

Thanks all, it is 15mA out of the driver, yes, disconnecting the power supply is the best way to cut off the current, but that's not my purpose.

With the 15mA, i can see very dim light coming out of the laser. ionlaser555 is right, 15ma is below the laser threshold, it is fine with my application.
cutechi 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 11:57 PM.


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