Testing current on DIY blu-ray

GooeyGus · Mar 9, 2008

So when one is testing for current, will the current change when the circuit is under load? For example, if you regulate the current to ~38mA with nothing connected, will that value drop when the laser diode is connected and operational? If so, should the circuit be at 38mA under load or 38mA before the diode is installed?

Gazoo · Mar 9, 2008

GooeyGus said:
So when one is testing for current, will the current change when the circuit is under load? For example, if you regulate the current to ~38mA with nothing connected, will that value drop when the laser diode is connected and operational? If so, should the circuit be at 38mA under load or 38mA before the diode is installed?

It should be set with a load connected. You can not regulate the current with nothing connected...where would the current go? We are lucky the LM317 can be used as a current regulator. We know what the current will be going to the load before the load is connected.

GooeyGus · Mar 9, 2008

Also, is it safe to test current on a rig that is already up and running with the diode soldered in? I'm still in the noob stage, I just dont want to fry this thing becuase I connected a multimeter wrong or something heh.

MB500 · Mar 9, 2008

As long as you open the circuit before you test the current it is ok. If you just touch two points you could short it.

GooeyGus · Mar 9, 2008

so... open circuit (for example: release switch) then attatch the leads, then hit the power again?

MB500 · Mar 9, 2008

The multimeter has to be completing the circuit. So unsolder it somewhere, and put the multimeter in the circuit there. If you measure the current like you would voltage you may short 2 points.

GooeyGus · Mar 10, 2008

Ahh.. ok now I gotcha. thanks!

Testing current on DIY blu-ray

GooeyGus

0

Gazoo

0

GooeyGus

0

MB500

0

GooeyGus

0

MB500

0

GooeyGus

0

Online statistics

Forum statistics

Share this page