Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

Buy Site Supporter Role (remove some ads) | LPF Donations

Links below open in new window

FrozenGate by Avery

help with simple ddl driver

bmw

bmw

0
Joined
Feb 16, 2011
Messages
86
Points
0
I made a simple ddl driver out of a diode (for revers voltage protection), a 16v 47uf capaciterfor voltage spikes),and a resistor(for current setting). I am going to use a loc diode and i want to run it 400ma. what value of resistor should I use? Will it work without a lm317?
 
Last edited:





i am not using a lm317 right now. do i have to use one. I was trying to do it with out a lm317 so i could use 2AA.
 
bmw said:
i am not using a lm317 right now. do i have to use one. I was trying to do it with out a lm317 so i could use 2AA.
Click to expand...
It would help if you let us know what you are using besides a
Rectifier Diode and a Capacitor and a Resistor...

Only those parts will not regulate the current to a Laser Diode
over the battery voltage variations over time...:cryyy:

Jerry
 
lol

It's tough to make an LM317 DDL circuit, without an LM317 ;)

Can you have a BMW without having a vehicle?

** Philosophy hurts head **
 
lol i feel stupid:o:banghead::oops: . well If i have a lm317 can I still use 2AA?
BTW, B.M.W. is my initials lol :D
 
Nope, 2AA won't give you enough voltage.

With an LM317, to drive a LOC, I suspect you would need 4, maybe 5 AA batteries.
 
ok i tried a 2.7 Ohm resistor but I only get 350ma. why is that?
 
2.7 ohms will give you around 470mA, possibly more. Not good. It'll kill your diode fast.

Use 3 ohms, or 3.3 ohms. Also, use lithium/lithium ion batteries. AAA's won't cut it. Sometimes, neither will AAs (bad quality, and/or empty ones).
 
i am using 4AA and a 2.7 Ohm resistor only gives me 350ma
 
You are not listening.

First of all, You're not feeding enough voltage to the driver. Well, it's there on the limit, but batteries could be drained a little.

Second, forget primary batteries. If what you're using is not rechargeable, it'll cost you A LOT OF MONEY! Trust me, I know firsthand.

Third, use 3.3 ohm unless you want your diode to die anywhere from instant to 1 minute runtime.
 
i am using alkaline AAs and i get about 6.5v. So according to Eudaimonium that is not enough voltage and or current to power this circuit properly. so if I power it with 2 3.6v AAs it should put out 400ma with a 3.1 Ohm resistor?
 
bmw said:
i am using alkaline AAs and i get about 6.5v. So according to Eudaimonium that is not enough voltage and or current to power this circuit properly. so if I power it with 2 3.6v AAs it should put out 400ma with a 3.1 Ohm resistor?
Click to expand...
If you mean, power them with two 14500 batteries (which are lithium-ion equivalents of AA size cells), yes it will work.

Fully charged lithium ion cells give off 4.2V of surface charge, too. Just something to keep in mind.
 
You must log in or register to reply here.





Back
Top