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Gear / Technical Help => Remote Power => Topic started by: Chuck on October 18, 2004, 10:25:31 AM

Title: Determining current draw
Post by: Chuck on October 18, 2004, 10:25:31 AM
I know there is a simple way to find how much current a device draws using a Volt/Ohm meter.
Does anyone know how to do this?
Title: Re: Determining current draw
Post by: leegeddy on October 18, 2004, 10:41:29 AM
I know there is a simple way to find how much current a device draws using a Volt/Ohm meter.
Does anyone know how to do this?

you really need a multimeter for ease of measuring. set your multimeter in series on the + side between the load (deck, pre, etc.) and the power source.

marc
Title: Re: Determining current draw
Post by: Chuck on October 18, 2004, 10:49:34 AM
...and use the appropriate resistance scale?
Title: Re: Determining current draw
Post by: leegeddy on October 18, 2004, 11:01:36 AM
...and use the appropriate resistance scale?

a multimeter can read current flow directly. no math is needed.

marc
Title: Re: Determining current draw
Post by: dklein on October 18, 2004, 11:37:25 AM
My old analog multimeter couldn't handle anything that drew more than 1 amp so I picked up one of these at the electronics store for ~$10.  You just place it 'in the circuit' so the current flows thru the meter.  Analog meters are kinda nice when things are fluctuating.
Title: Re: Determining current draw
Post by: leegeddy on October 18, 2004, 11:52:23 AM
My old analog multimeter couldn't handle anything that drew more than 1 amp so I picked up one of these at the electronics store for ~$10.  You just place it 'in the circuit' so the current flows thru the meter.  Analog meters are kinda nice when things are fluctuating.

damn, that's old school  :)

..getting flashbacks of science classes.

marc
Title: Re: Determining current draw
Post by: Chuck on October 18, 2004, 12:30:50 PM
I've only got analog multimeters.
Title: Re: Determining current draw
Post by: Chuck on October 18, 2004, 12:34:34 PM
My old analog multimeter couldn't handle anything that drew more than 1 amp so I picked up one of these at the electronics store for ~$10.  You just place it 'in the circuit' so the current flows thru the meter.  Analog meters are kinda nice when things are fluctuating.

Does a Mini-Me or a DAT deck draw more than 1 amp?
Title: Re: Determining current draw
Post by: Brian Skalinder on October 18, 2004, 12:42:28 PM
Does a Mini-Me or a DAT deck draw more than 1 amp?

Ahem.  :P  http://www.taperssection.com/yabbse/index.php?topic=2461.0
Title: Re: Determining current draw
Post by: Chuck on October 18, 2004, 12:47:18 PM
Thanks Brian... you are always there with the right link... :)
That Mini-Me spec is hard to come by. I couldn't find a published number anywhere, including my manual and their web site.
Title: Re: Determining current draw
Post by: Brian Skalinder on October 18, 2004, 12:52:00 PM
That Mini-Me spec is hard to come by.

Yeah it is.  Had to call Apogee directly to get that one and pry it out of 'em.  They didn't want to give out *any* number as it varies depending on the gear used, but I finally nailed 'em down to a rough number.
Title: Re: Determining current draw
Post by: Chuck on October 18, 2004, 12:58:05 PM
Thank you for doing that research. +T
Title: Re: Determining current draw
Post by: dklein on October 18, 2004, 03:52:44 PM
Yeah it is.  Had to call Apogee directly to get that one and pry it out of 'em.  They didn't want to give out *any* number as it varies depending on the gear used, but I finally nailed 'em down to a rough number.

There is some truth to that - different mics draw different amounts of phantom and the consumption goes way up when you crank the gain and push more output.  If you turn the gain way up the ammeter behaves more like a VU meter, bouncing around with the music.  But they should have at least provided a range.
Title: Re: Determining current draw
Post by: Brian Skalinder on October 18, 2004, 04:04:50 PM
There is some truth to that - different mics draw different amounts of phantom and the consumption goes way up when you crank the gain and push more output.  If you turn the gain way up the ammeter behaves more like a VU meter, bouncing around with the music.  But they should have at least provided a range.

Definitely truth, but yeah - a published range would be nice like (ahem!) Grace Design offers.  :)
Title: Re: Determining current draw
Post by: leegeddy on October 18, 2004, 09:46:31 PM
>>There is some truth to that - different mics draw different amounts of phantom and the consumption goes way up when you crank the gain and push more output.

absolutely. this is why designers usually post typical/average current draw (or power consumption) in their specs.

marc
Title: Re: Determining current draw
Post by: Simp-Dawg on October 25, 2004, 10:59:29 PM
so, can someone tell me how to use this model multimeter to test current draw?

can this be used to test remaining charge on batteries as well?
Title: Re: Determining current draw
Post by: leegeddy on October 26, 2004, 12:04:18 AM
>>so, can someone tell me how to use this model multimeter to test current draw?

the setup is for current draw greater than 200mA. if it's less, switch to 200mA and use the other + terminal.

>>can this be used to test remaining charge on batteries as well?

no.

marc

edit:
on second thought....if the multimeter gives you a negative #, then reverse the terminals.  i -think- ammeters are designed to read - to + as a positive current flow and + to - as a negative current flow. not 100% about the one you have.  it really doesn't matter. just take the readout and ignore the - or +.