Patent ID: 11881381
Assignee: LAM RESEARCH CORPORATION
Field: Measurement (Instruments)
Classification: CPC H  C  G | IPC C  G  H

Claim 19:
20. A device for measuring a capacitance of a capacitor without disconnecting the capacitor from a circuit for distributing RF power at a first target frequency, the device comprising:
a filter including a passband including a first frequency greater than a 10th harmonic frequency of the first target frequency, the filter also having a stopband including the first target frequency;
an oscillator for generating an alternating voltage (Vin) at the first frequency (ω);
a resistance (R), wherein an output of the oscillator is coupled to a first terminal of the resistance (R), and a second terminal of the resistance (R) is coupled to the filter that is electrically coupled in series with the capacitor; and
a voltage measurement interface for measuring a filtered signal (Vout) at the second terminal of the resistance (R), wherein a measured capacitance value (C) of the capacitor is based in part on the resistance (R), the first frequency (ω), and the alternating voltage (Vin), where Vout/Vin=1/(1+jωRC).