how to determine mA

[mikey395]

hi ive been having bit of trouble lately on how to find or measure how much mA i should feed the circuit i managed to find the current that travels through the resistors, can some1 show how to determine the mA that goes through a laser ive been using ohms law I=V/R but i still am having trouble
i am plannin to use 6 0r 9 volts i have 2 10ohm resistors in parrallel
So . .
I=V/R
I=9/5
then i get 1.8A?

this is were i get stuck, at the symbol

 

[Fiddy]

Good Hello,

what driver are you using?
are you trying to measure/calculate output or input current?

 

[mikey395]

i want to measure how much current is going to be running through the circuit this is the driver i will be using/making

 

[mikey395]

Driver.jpg (image)http://3.bp.blogspot.com/_4wHo2MPDwAc/R2YuBFTq09I/AAAAAAAAAAU/4FCiHm71rQE/s1600-h/Driver.jpg

 

[Fiddy]

It will be dependent of those resistors, use a calculator like this:http://www.reuk.co.uk/LM317-Current-Calculator.htm to calculate the resistor values for you desired current.

 

[lasersbee]

FIRST..... you will need a Test Load to adjust the current or
you will blow your Laser Diode...

SECOND...
there are tons of posts on how to test for current...
You will at least need to TRY to do a little research and reading
on the Forum...

This should get you started.... (It was an easy find)....

http://laserpointerforums.com/f38/first-build-phr-803t-64962.html#post934196


Jerry

 

[mikey395]

yes this helps alot thank you
isnt the pic i put up abit similar to ur driver?

 

[lasersbee]

That's not my driver.... It is a generic Linear DDL type
current regulated driver...

A bit of research and reading would have got you this...

http://laserpointerforums.com/f42/diy-homemade-laser-diode-driver-26339.html#post280371


Jerry