Calculate the cutoff frequency of a first-order low-pass filter for R1 = 2.5kΩ and C1 = 0.05μF___________? December 17, 2018 – by admin Calculate the cutoff frequency of a first-order low-pass filter for R1 = 2.5kΩ and C1 = 0.05μF___________? A. 1.273kHz B. 12.73kHz C. 127.3 kHz D. 127.3 Hz