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Online RC Lowpass filter Calculator


Figure1 shows a lowpass filter made from a RC section, It's cutoff frequency is shown below

formula 1

formula 1

Figure 1

Figure 1

Figure2 is a lowpass filter using a single opamp, and a single power supply. C2 is a capacitor with high capacity. The voltage amplification factor of this circuit is R1/R2. The cutoff frequency of figure 2 is same with figure 1

lowpass filter schematic

Figure 2

Figure 3 is a simulation result When R1=R2=15915Ohm, C1=10nF (The cutoff frequency is 1K). Gain=1, 0.707V is cutoff frequency point

Reponse curve

Figure 3

Input C1, R1 to calculate cutoff frequency F:

Capacitor C
Resistor R
    
Cutoff Frequency f  

Input C1, cutoff frequency F to calculate R1:

Capacitor C
Cutoff Frequency f
    
Resistor R  


Related:
>>Bandpass Filter Calculator
>>highpass Filter Calculator

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