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

Quick questions about the lm317 driver. Yes, I do need your help again :D

  • Thread starter Thread starter Deleted member 8382
  • Start date Start date
now I think there's a third variable, the multimeter. One shows 75mA~ and the other 100mA~

Now I think it's about matches+driver+multimeter, which is a a huge problem with all together >.>

Btw, I've seen adrian used a plastic tube to fit the CR2 batteries inside the barrel. Do anyone know where could I get a larger piece of this plastic?

Yours,
Albert
 





Just as suggestion, instead use LM317, that have an excessive dropout, why you don't use an LM1117 ?

It have a dropout of only 800 / 900 mV, so 2x3.6V are enough also for blu-ray diodes, and are perfectly pin-equivalent of the 317 :)


@ Hallucinogenic: better use a more easy and precise way for measure current ..... put a 1ohm, 1 watt, 0,5% resistor in serie of your diode, then measure the voltage drop at the resistor leads with a digital multimeter ..... each mV is 1 mA, with the precision of the resistor (0,5%) ..... plus the tolerance of the DMM, ofcourse :)
 
Last edited:
Hallucynogenyc said:
now I think there's a third variable, the multimeter. One shows 75mA~ and the other 100mA~

Now I think it's about matches+driver+multimeter, which is a a huge problem with all together >.>

Btw, I've seen adrian used a plastic tube to fit the CR2 batteries inside the barrel. Do anyone know where could I get a larger piece of this plastic?

Yours,
Albert
Click to expand...

To test your multimeters you could hook up a test load with your meter in series and given a known output from your PSU that should eliminate one of the variables.
 
Ways said:
To test your multimeters you could hook up a test load with your meter in series and given a known output from your PSU that should eliminate one of the variables.
Click to expand...

The problem is that the PSU, as you can see on the video, is somehow old and the voltimeter on it is analogic xD. Measuring voltages up to 1V is no problem, but it seems like one multimeter give 20mV more than the other. :/
 
Try swapping the leads from one meter to the other, you may find that, if they are old, thery are effecting the readings.

Regards rog8811
 
You must log in or register to reply here.





Back
Top