undertaker
Newly Enlightened
- Joined
- Nov 23, 2004
- Messages
- 25
hi all,in a keychain laserpointer,who many "ma" it works?are "ma" diferent in a laserpointer with 2 AAA batterys?
ampers
- Thread starter undertaker
- Start date
Depends on the circuit and diode being used.
Some of the "driver boards" for the red pointers use nothing more than a single resistor. A quick google search gave me a link to a 650nM(red) diode that only requires 30mA, couple that with three lr44 batteries and the correct resistor and you can lase for days.
Some of the "driver boards" for the red pointers use nothing more than a single resistor. A quick google search gave me a link to a 650nM(red) diode that only requires 30mA, couple that with three lr44 batteries and the correct resistor and you can lase for days.
The_LED_Museum
*Retired*
Re: amperes
I've had red (~640nm) laser diodes that fully lased with just 25mA of drive current. I believe they were designed to go in keychain laser pointers; though any application calling for a <5mW red diode laser would be likely candidates. I believe they came from Roithner Lasertechnik in Austria.
A 635nm pen-style pointer I got from Abeland in November 2003 drew 41mA from its two AAA cells.
I've had red (~640nm) laser diodes that fully lased with just 25mA of drive current. I believe they were designed to go in keychain laser pointers; though any application calling for a <5mW red diode laser would be likely candidates. I believe they came from Roithner Lasertechnik in Austria.
A 635nm pen-style pointer I got from Abeland in November 2003 drew 41mA from its two AAA cells.
undertaker
Newly Enlightened
- Joined
- Nov 23, 2004
- Messages
- 25
Re: amperes
well i just f...up a keychain laserpointer right now...i plugged a ac/dc adaptor with 4.5 volts /600 ma and the laserpointer start dimming and past away silently...GOD bless is diode!So i started the autopsy and im asking WHY?if a keychain laises at 4.5 volts,what went wrong?Funeral is friday...
well i just f...up a keychain laserpointer right now...i plugged a ac/dc adaptor with 4.5 volts /600 ma and the laserpointer start dimming and past away silently...GOD bless is diode!So i started the autopsy and im asking WHY?if a keychain laises at 4.5 volts,what went wrong?Funeral is friday...
Enigmahack
Newly Enlightened
- Joined
- Nov 12, 2004
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- 139
Re: amperes
[ QUOTE ]
undertaker said:... adaptor with 4.5 volts /600 ma...
[/ QUOTE ]
I'm no rocket scientist but the diode was ment to handle 20-35 ma and you gave it 600?
You can draw your on conclusion from here /ubbthreads/images/graemlins/wink.gif
[ QUOTE ]
undertaker said:... adaptor with 4.5 volts /600 ma...
[/ QUOTE ]
I'm no rocket scientist but the diode was ment to handle 20-35 ma and you gave it 600?
You can draw your on conclusion from here /ubbthreads/images/graemlins/wink.gif
Re: amperes
Why, oh why? /ubbthreads/images/graemlins/mecry.gif what have I done to this poor diode to deserve this.
Yes sounds familiar - sniff. In the good old days when red lasers ruled, I tried a similiar thing...so thats why they call you undertaker /ubbthreads/images/graemlins/ohgeez.gif I need sleep, I'm seeing green everywhere now...
Why, oh why? /ubbthreads/images/graemlins/mecry.gif what have I done to this poor diode to deserve this.
Yes sounds familiar - sniff. In the good old days when red lasers ruled, I tried a similiar thing...so thats why they call you undertaker /ubbthreads/images/graemlins/ohgeez.gif I need sleep, I'm seeing green everywhere now...
undertaker
Newly Enlightened
- Joined
- Nov 23, 2004
- Messages
- 25
Re: amperes
but my friends,let me tell you that i have another keychain laser working with a ac/dc adaptor at 3 volts (regulated) at 600 ma and its working well...
but my friends,let me tell you that i have another keychain laser working with a ac/dc adaptor at 3 volts (regulated) at 600 ma and its working well...
Re: amperes
[ QUOTE ]
Enigmahack said:
[ QUOTE ]
undertaker said:... adaptor with 4.5 volts /600 ma...
[/ QUOTE ]
I'm no rocket scientist but the diode was ment to handle 20-35 ma and you gave it 600?
You can draw your on conclusion from here /ubbthreads/images/graemlins/wink.gif
[/ QUOTE ]
According to Ohms law you cannot overpower a 4.5V resistance load with another 4.5V source, if it truly is a resistance load. If there is a regulator on the circuit board then you cannot use Ohms law without some precise measurements.
My guess is that your adapter is not regulated and it may have introduced ripple to your laser, resulting in overvoltage pulses that slowly killed your laser.
The diodes that I have killed just go out in an instant. Perhaps this is your answer.
[ QUOTE ]
Enigmahack said:
[ QUOTE ]
undertaker said:... adaptor with 4.5 volts /600 ma...
[/ QUOTE ]
I'm no rocket scientist but the diode was ment to handle 20-35 ma and you gave it 600?
You can draw your on conclusion from here /ubbthreads/images/graemlins/wink.gif
[/ QUOTE ]
According to Ohms law you cannot overpower a 4.5V resistance load with another 4.5V source, if it truly is a resistance load. If there is a regulator on the circuit board then you cannot use Ohms law without some precise measurements.
My guess is that your adapter is not regulated and it may have introduced ripple to your laser, resulting in overvoltage pulses that slowly killed your laser.
The diodes that I have killed just go out in an instant. Perhaps this is your answer.
WildRice
Flashlight Enthusiast
Re: amperes
The 600mA on the transformer is only the amound of power it CAN sypply. It dosent mean it was pushing 600mA into the diode. When running on button calls, internal resistance plays ALOT. The LR41 batteries cant sustain much power. ie put a meter across it in the current setting and you wont see much current (less than 50mA I would guess). Now take a regular AA battery (same vltage as the button cell 1.5volts) and measure the current. It WILL be MUCH more. the AA battery can provide more power at a given load. LED's and LASER diodes are current driven devices, not voltage driven. you could run a 1.7vold LED off of 12 volts with a dropping resistor to limit the CURRENT. when you put the LASER on the transformer it wanted to pull as much current as it could. the LR41 batteries limited its draw to probably 30 or 40mA, but the transformer gave it more than it could handle....RIP
Hope this helps.
Jeff
The 600mA on the transformer is only the amound of power it CAN sypply. It dosent mean it was pushing 600mA into the diode. When running on button calls, internal resistance plays ALOT. The LR41 batteries cant sustain much power. ie put a meter across it in the current setting and you wont see much current (less than 50mA I would guess). Now take a regular AA battery (same vltage as the button cell 1.5volts) and measure the current. It WILL be MUCH more. the AA battery can provide more power at a given load. LED's and LASER diodes are current driven devices, not voltage driven. you could run a 1.7vold LED off of 12 volts with a dropping resistor to limit the CURRENT. when you put the LASER on the transformer it wanted to pull as much current as it could. the LR41 batteries limited its draw to probably 30 or 40mA, but the transformer gave it more than it could handle....RIP
Hope this helps.
Jeff
Re: amperes
[ QUOTE ]
WildRice said:
Now take a regular AA battery (same vltage as the button cell 1.5volts) and measure the current. It WILL be MUCH more. the AA battery can provide more power at a given load. LED's and LASER diodes are current driven devices, not voltage driven. you could run a 1.7vold LED off of 12 volts with a dropping resistor to limit the CURRENT. when you put the LASER on the transformer it wanted to pull as much current as it could.
Jeff
[/ QUOTE ]
Fresh and/or rested Sony "Stamina" AA NI-MH batteries drop about 5.2 amps. I love those batteries.
And believe it or not, laser diodes are disgustingly sensitive to overvolt conditions, even when the current is balanced to equate the same wattage.
Some of the larger (>20W) have voltage tolerances like 2.1v min, 2.2v operating, 2.3v max. Thats why I have a hard time buying anything like that off ebay. They are so easy to destroy. Weak AA batteries or the static you collected from the doorknob can cause immedieate catastrophic failure.
Just think of how many laser diodes youve seen on ebay that come untested with descriptions like "got it at a surplus auction" or "only ran once @ 50% power" ...
...Little blue hair lady only drives it to church on Sunday type descriptions...
Another word of wisdom, if you see the diode sitting on anything other than an optical table or out of its static free packaging assume its dead. 9 times out of 10 you will be right.
[ QUOTE ]
WildRice said:
Now take a regular AA battery (same vltage as the button cell 1.5volts) and measure the current. It WILL be MUCH more. the AA battery can provide more power at a given load. LED's and LASER diodes are current driven devices, not voltage driven. you could run a 1.7vold LED off of 12 volts with a dropping resistor to limit the CURRENT. when you put the LASER on the transformer it wanted to pull as much current as it could.
Jeff
[/ QUOTE ]
Fresh and/or rested Sony "Stamina" AA NI-MH batteries drop about 5.2 amps. I love those batteries.
And believe it or not, laser diodes are disgustingly sensitive to overvolt conditions, even when the current is balanced to equate the same wattage.
Some of the larger (>20W) have voltage tolerances like 2.1v min, 2.2v operating, 2.3v max. Thats why I have a hard time buying anything like that off ebay. They are so easy to destroy. Weak AA batteries or the static you collected from the doorknob can cause immedieate catastrophic failure.
Just think of how many laser diodes youve seen on ebay that come untested with descriptions like "got it at a surplus auction" or "only ran once @ 50% power" ...
...Little blue hair lady only drives it to church on Sunday type descriptions...
Another word of wisdom, if you see the diode sitting on anything other than an optical table or out of its static free packaging assume its dead. 9 times out of 10 you will be right.
WildRice
Flashlight Enthusiast
Re: amperes
Spec, you are correct about the voltage levels. Their power output curve is very steep at the operating range, and unlike LED's that will shift colors and dim out when given too much 'power', they will still somewhat work. not true for LD's, once dead, always dead. I was trying to explain that 4.5volts from LR41 batteries will power a pen laser OK, but 4.5 from alky AA's probably wont be good.
Jeff
Spec, you are correct about the voltage levels. Their power output curve is very steep at the operating range, and unlike LED's that will shift colors and dim out when given too much 'power', they will still somewhat work. not true for LD's, once dead, always dead. I was trying to explain that 4.5volts from LR41 batteries will power a pen laser OK, but 4.5 from alky AA's probably wont be good.
Jeff
djpark
Enlightened
Re: amperes
It may be the thread I was looking. I am hoping to find an answer.
I have a white led + red laser pointer put together with 4 LR41 batteries. The laser led has 3 legs in a casing and there is COB (chip on board) controller for the laser with a trimmer.
With bench PS at 3.5V, I could adjust the current supply between 0 and well over 70mA to laser controller. Currently it draws about 60mA from the 4 LR41 battery set.
How is the expected power output calculated?
-- dj
It may be the thread I was looking. I am hoping to find an answer.
I have a white led + red laser pointer put together with 4 LR41 batteries. The laser led has 3 legs in a casing and there is COB (chip on board) controller for the laser with a trimmer.
With bench PS at 3.5V, I could adjust the current supply between 0 and well over 70mA to laser controller. Currently it draws about 60mA from the 4 LR41 battery set.
How is the expected power output calculated?
-- dj
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