An electrostatic force generator is disclosed. The electrostatic force generator includes an RF AC voltage source, a capacitive module, a resonant capacitive-inductive bridge (CIB) module, a lock-in amplifier module, and a proportional-integral-derivative (PID) controller. The resonant capacitive-inductive bridge module converts the differential capacitance to a differential signal. The differential signal from the resonant capacitive-inductive bridge module is demodulated at the RF excitation frequency by the lock-in amplifier module. The PID controller receives the output signal from the lock-in amplifier module and generates two audio frequency AC signals to generate a compensation electrostatic force and maintain the capacitance balance inside the capacitive module.