RC Low Pass Filters block high frequency signals. As we increase the frequency of the voltage source we notice that the output signal is reduced. Low Pass Filters will allow lower frequencies to pass with little distortion. The range of frequencies that get blocked or "pass" are affected by the resistance and capacitance values.
For Example in the circuit we have a 1k resistor and a 1μF capacitor. The equation to find the cut-off frequency of the filter is
f = 1/2πRC Hz or ω = 1/RC.
This is the frequency at which the circuit will pose higher resistance in frequencies over 1kHz for 1k resistor and 1μF capacitor and there is also a phase shift which can be calculated from φ = -arctan(2pfRC)
