1.) Consider a 1st order RC-low pass filter where the C is fixed but R is variable. How will the cut-off frequency change when a) R is minimum? and b) R is maximum? Sketch qualitatively the characteristics.

2.) A low pass filter (LPF) is to be designed with C= 0.01 microfarad and a cut-off frequency of 1000 Hz. What value of R is to be used?

Question

1.) Consider a 1st order RC-low pass filter where the C is fixed but R is variable. How will the cut-off frequency change when a) R is minimum? and b) R is maximum? Sketch qualitatively the characteristics.        

2.) A low pass filter (LPF) is to be designed with C= 0.01 microfarad and a cut-off frequency of 1000 Hz. What value of R is to be used?

radar · Answer

The formula for Fc of a 1st order RC low pass filter is  Fc=1/(2PiRC) for part 1 analyze the behavior of Fc as R is varied both low and high.

radar · Answer

For 2.) substitute 1,000 for Fc and 10^-8 for C and solve for R

radar · Answer

I would guess a 5% 16KOhm resistor would suffice.

anonymous · Answer

how to sketch the characteristic in no. 1 question?

radar · Answer

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