# Using the ZXCT1107/1109/1110 High-Side Current Monitor

Hi,

Can somebody please explain to me how to calculate the gain of the ZXCT1107/1109/1110 High-Side Current Monitor?
I am trying to build a circuit that will measure the current and voltage of a solar panel. I would like to use the ZXCT1107/1109/1110 to measure the current.

Thanks

Hi, it helps if you post a link to a data sheet.

They give you a set of equations and an example to use, it depends on your Rs and what you want your output voltage range to be.

Are you using a MPPT or charge controller on the PV panel, if so be careful because most switch the negative side of the PV panel not the positive side, as assumed by most, to the battery. This will cause problems when measuring the PV panel voltage.

I ask, do you want to measure the charging current of the PV panel to batteries, and PV panel voltage to batteries?
If so then when charging, PV panel volts will equal battery voltage, you can measure current on the negative line between the controller and batteries for PV panel current. if you are not using MPPT controller.

Tom......

I have looked at the data sheet, but I am still confused on how to calculate the gain. My Rgain resistor is 13K and my Rsense resistor is a 0.1.
I am actually trying to measure the current flowing through a load connected to a small solar panel. I am not trying to charge any batteries, but instead use the panel for small applications such as a small DC motor. I am using an Arduino Nano to record the data.

Thanks

Hi, okay, good nice and simple setup.
We need to know, what the max panel current will be measuring and what output voltage you want across the gain resistor.
We cannot tell you if your calculation is correct without these parameters.

Tom.....

The max current will be around 550mA. I would like the voltage across the gain resistor to be somewhere between 2V and 5V.

Thank you