Digital Multimeters (DMMs) and Precision DC Sources

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measuring residual voltage with Keithley 2400

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Hello,

 

I'm relatively new at Labview and am looking for assistance.  I would like to apply a specified voltage to a circuit for a given amount of time, then cut off the voltage and measure the voltage in the circuit as it dies off.  Most examples and problems I've seen here involve measing I or V while sourcing V or I at the same time.

 

I"ve attempted a few simple Labview programs with the NI-provided Keithley VIs, but can't get my program to do what I want.

 

Any assistance is appreciated.  Thank you.

 

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Possible AND easy. Source current to put the smu in limit or compliance (this will be source voltage at the limit value). Then set the compliance or limit to ZERO and you will be measuring the residual voltage. Do this on the lowest current range possible for best results.

 

You might want to contact keithley Applications if you need more info on this.

 

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More response from Keithley - so just contact them. I am the piggy-in-the-middle right now.

 

Sounds like what he wants to do is configure the 2400 to source voltage for a while then switch it over to a 0A current source and then measure the voltage as it dies off.  This is simple enough to do.

 

Depending on how sensitive the device is, this straight forward approach may not work due to the function change and how the circuit may be loaded during that change.  In that case I would say configure the 2400 as a current source with a voltage limit at the voltage you want applied to the circuit then set the current level high enough so the SMU hits this voltage limit and stays there.  When you want to switch over to measuring the voltage as it dies off, simply change the current level to 0A.  This should avoid any nastiness on the output you might get if you explicitly changed from a V source to an I source.

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Setting it up as a current source with a voltage limit and then measuring the voltage did precisely what I wanted.  Thanks for the help!

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