What is cutoff frequency of a filter?

This “Cut-off”, “Corner” or “Breakpoint” frequency is defined as being the frequency point where the capacitive reactance and resistance are equal , R = Xc = 4k7Ω. When this occurs the output signal is attenuated to 70.7% of the input signal value or -3dB (20 log (Vout/Vin)) of the input.

In electronics, cutoff frequency or corner frequency is the frequency either above or below which the power output of a circuit, such as a line, amplifier, or electronic filter has fallen to a given proportion of the power in the passband.

The cut-off frequency, corner frequency or -3dB point of a high pass filter can be found using the standard formula of: ƒc = 1/(2πRC) . The phase angle of the resulting output signal at ƒc is +45o.

Calculate cutoff frequency of low pass filter The cutoff frequency denotes the frequency at which the two values are equal, ie R = X_C . Thus, at a frequency above the cutoff frequency, X_C is less than R, at a lower frequency, X_C is greater than R.