PXI-4461 minimum working load

[matthorne83]

This spec sheet (sheet 18) says Minimum working load 600 ohms.

https://www.ni.com/pdf/manuals/373770k.pdf

That spec isn't described. Can someone explain what that means?

Thanks

[santo_13]

In short, the load has to be >= 600 ohms for the AO to operate within specifications.

I would have interpret the words as load < 600 ohms, as the maximum load will have a lower impedance but it does not make sense electrically.

Logically speaking it could not drive loads higher than 600 ohms, for example, it cannot drive an 8-ohm speaker directly as a lot of current will be required to attain the requested voltage. The datasheet does not specify a typical or max drive current, based on the voltage range and this minimum working load, I would say it is +/- 60mA maximum.

Comparing to other DSA cards (4463), they specify a max drive current, 

And other AC specifications are defined for various loads,

[Junior.silva77]

After doing some tests, I saw that the PXI 4461 board has a current limiter, when it approaches 25 mA RMS it gradually increases the internal impedance, limiting the current at that level.