Physlet Illustration: Filters

 

 
Circuit A Circuit B Circuit C Circuit D
In this simulation, a 100 W resistor and a 50 mH inductor or 10 microF capacitor are connected in series with a 10-Volt (maximum) AC source. The graph shows the output voltage as measured by the oscilloscope across one of the components (depending upon the circuit).  Vary the value of the source's angular frequency (5 rad/s < w < 10,000 rad/s ) using the slider. Which circuit(s) can be used as a low-pass filter?  Which a high-pass filter?

Hints:

  1. Select a circuit with the radio button and change the frequency to see how the output changes.  
  2. To verify that the output is as expected, you will need to first determine the impedance, current, and finally the voltage drop across the output.  
  3. Try the different circuits.  Which circuits exhibit similar behavior?   
  4. Are these filters exactly the same?

Reference

See Walker, Section 24-3 & 24-4

Illustration written by Chuck Niederriter