NI-6739 AO

[shiksri]

I wanted to know what is the output impedance of of a AO in 6739 when it is kept disabled meaning it is not forcing anything.

[OEryashar]

When the analog output (AO) of the NI PXI-6739 is disabled, it enters a high-impedance state.

So to answer your question, the output impedance is very high, effectively isolating the output from the circuit.

Note; This high-impedance state ensures minimal current flow and prevents the AO from influencing the rest of the circuit. 

I hope that satisfies your question!