Capacitive system ground

AN3150

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DocID17048 Rev 3

Figure 4. Equivalent connected to earth application schematic

intrinsic to the power network. They usually have relatively high values and are seen as a

short from a touch sense capacitance measurement.

The values of these capacitances depend on the power supply design of the application. For

example, they may include the capacitance between the primary and secondary coils of a

transformer.

system. However, in some specific designs it is possible to improve the sensitivity by adding

a physical capacitor across the power supply.

3.2

Portable applications

In portable configuration, It helps to consider the user’s potential as a reference point

and the application ground, see Figure 5: Equivalent portable application schematic.

The user’s potential includes some stray capacitances like the one between the user’s hand

and the battery.

that the further the module is removed from earth, the weaker the coupling between the

applications.

ai17443V2

Application

Electrode