Measurement Computing CIO-DI48 - Manual (Page 22)

interference associated with line voltage (60 Hz) would be filtered out but a signal of
25 Hz would be allowed to pass.
In digital input circuits, low-pass filters are sometimes used to “de-bounce” inputs
from relay or switch contacts.
A simple low-pass filter may be constructed from one resistor (R) and one capacitor
(C). The cut-off frequency is determined by the formula:
Fc = 1
2 *
π * R * C
R = 1
2*
π * C * Fc
Where π = 3.14...
Fc = frequency in cycles per second
R = resistance in Ohms
C = capacitance in Farads
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