Measuring The Current Draw?

How would you go about measuring the current draw on a leadlight 105? Sorry if this has been said before and or very simple to test, but I searched for it and was unable to find any posts concerning this issue.

Hold the laser pointer so its "business-end" (laser aperture) points at the floor.
Unscrew the tailcap and throw it in the garba...er...um...set it aside.

Be certain there are known-new cells (batteries) in the pointer.

Set your DMM on one of the low amp scales (the 4 amp scale on mine is appropriate), and plug the leads into the DMM (black in the (-) or common receptacle, red in the receptacle for amperes).

Place the end of the black lead on the metal clip on the side of the pointer's body, and the end of the red lead on the (+) positive nipple of the battery in the pointer, push & hold the button on the laser pointer's body, and note what the meter displays.

If the meter displays 0.540, the laser pointer's current consumption is 540mA.

Apperently i have no idea what to put the DMM on so heres a pic of mine. Maybe someone could tell me which setting? Also i found this odd, when i do the method to check the draw and place the setting on 200m and push the button on the pointer it turns on, but no other setting will do this..odd? Oh and as you can tell i had to put my sexy pointer in the pic...im such a nerd lol

Put your DMM on the 10A scale (one click counterclockwise from the "200m" setting) and try the measurement again. /ubbthreads/images/graemlins/smile.gif

sadly the 10A setting would not give any results it just stays at 0.00. When i put it on other settings it will move around but not on that one. Also when i put the DMM on in the mA range it just shows |1__._| and wont give any reading at all. If i use an AAA battery it will give readings on the 20k 200k 2000K but not on the 200 or 2000 in the mA section. Wonder if the DMM is broken? I dont know all that much about electricity so you may have to bare with me

The bottom part of your DMM can't be seen in your photo, but an empty socket is visible. My DMM has 3 sockets and to use the 10A setting, I have to move the red wire from its normal socket to the special 10A, which happens to be the top one of the 3. Maybe its the same for yours ?

I did the current measurement as per Craig/LED_Museum's description on my 25mW pointer and got a 0.310 reading, meaning 310mA as I understand it.

Cheers,
Erling

EGP i put the red in the emtpy sock and i recieved a reading of 0.33 could this be 330mA? If so would that be bad or good for a 40mW lealight?

I would think so (330mA), and would also believe it's ok for a 40mW pointer. As I understand it, the current should not be much over 300mA, unless the pointer is made with a beefier diode than the standard 5mW types. Others will know this for sure, so hopefully they will chime in too.

Cheers,
Erling

Hi, my meter only messures up to 200MA and then jumps to 10A,so i cant messure the current right? i just won a meter on ebay and it appears that this messures the same range as the one i have already doh
Nick

rexer said:

Hi, my meter only messures up to 200MA and then jumps to 10A,so i cant messure the current right? i just won a meter on ebay and it appears that this messures the same range as the one i have already doh
Nick

Click to expand...

Same case with Clifto. Which means your laser is drawing more than 200mA. Set it to 10A, eg 0.33 = 330mA, 0.25 = 250mA.

never mind...

rexer said:

Hi, my meter only messures up to 200MA and then jumps to 10A,so i cant messure the current right? i just won a meter on ebay and it appears that this messures the same range as the one i have already doh
Nick

Click to expand...

There should also be a seperate hole (female jack) in the meter's body just for taking measurements on the 10A scale. Plug the red meter lead into this jack, leave the black meter lead where it is now (negative/common or -/com), set the dial for 10 amps DC, and measure as described earlier.

i blew the 10A socket on my meter ages ago , pluged in the wrong hole and tested car electrics DOH! never mind got a cheapy on the way from fleabay.
cheers mate.
Nick

rexer said:

i blew the 10A socket on my meter ages ago , pluged in the wrong hole and tested car electrics DOH! never mind got a cheapy on the way from fleabay.
cheers mate.
Nick

Click to expand...

If the meter is still working, then most probably you just blew a fuse inside.

Ken83 said:

If the meter is still working, then most probably you just blew a fuse inside.

Click to expand...

Open the box, chack the fuse and check for burns or melting on a resistor or a ferrite core

I replaced a resistor once on my meter by cutting the old one loose and solder a wired one on the side...still works...

until someone stupid checked a thermo fuse under the coffee machine and shorted [burnt a hole] on the test leads...the things fried, bought a new one

Someone sent me this when I asked for current draw



hope its of use

delete this, Its intended purpose was for LED forum

I dont know how i stumbled into the lasers forum...

Thanks, good to know info !