FDC2114: Choosing the right resonant frequency

Harry128

Part Number: FDC2114
Other Parts Discussed in Thread: FDC1004

Hi TI,

How to choose the resonant frequency (excitation frequency) properly for working with different type of liquids? For example would higher freq work better for certain conductive liquid?

Any practical approach for me to design the LC tank properly?

Thanks,

Harry

over 3 years ago

0 Sharath Vallamkonda over 3 years ago

TI__Expert 3435 points

Hi Harry,

You can design the LC tank so that it is not at extreme (10k or 10M Hz) when the liquid is at the lowest or highest level. You can test it with an EVM with the expected liquid levels and adjust LC tank accordingly.

Regards

Sharath.

0 Harry128 over 3 years ago in reply to Sharath Vallamkonda

Prodigy 70 points

Hi Sharath,

Thank you for the quick reply.

Let's say I have an LC tank built with a few kHz resonant freq but it does not vary much with different liquid levels. I then rebuild the LC tank and move its freq to a few MHz. It works much better in terms of freq variations. I guess my question is more on what is the correlation between liquid characteristics and excitation freq? Any practical study on that?

Thanks,

Harry

0 Sharath Vallamkonda over 3 years ago in reply to Harry128

TI__Expert 3435 points

Hi Harry,

We are suggesting FDC1004 for liquid level sensing. Please refer to https://www.ti.com/lit/pdf/snoa925

Sensors

Sensors forum

FDC2114: Choosing the right resonant frequency