SR-830 and the Three Omega Technique .. #2

Thread Starter


Joined Sep 2, 2022
Hello all,

I am doing research at Illinois State University in the field of thermoelectrics and we have been trying to apply the Three Omega Technique, but we have met with limited success.

The system is as follows:
An SR-830 Lock-In Amplifier is utilized to both create and read a signal frequency.
The signal goes through a 10Ω resistor.
The frequency is sent to a four-point sample that is heated.
The return signal is sent back to the lock-in and the signal voltage and phase are read off the displays.

Now my question lies in how exactly a person might measure the three omega signal from this setup, as we get results of voltages in the mV range when they should be in the μV range for the 3ω signal. :(

Do we need to use an external function generator to input a 1ω signal and just read the 3ω from the lock-in?

Also, I have attempted to contact SRS and they did not entirely answer my questions due to their not exactly knowing the technique in question.

Any help for the technique or the system would be greatly appreciated!

Thank you in advance!

Hello Josh

Hope you have figured out the issue. I have another problem with the same setup. SR830 does not provide a steady v3(rms) at a particular frequency for a constant v0. After every iteration it changes by orders. Can anyone please help me with this issue?


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