Active Filters

Abstract

Filters are frequency selective circuits. This means that they deliberately allow or block a range of frequencies while passing from input to output. Passive filters were circuits that accomplish this task by utilization of passive circuit elements such as R,L, and C. The maximum gain of the output signal is 100% of the input signal when operated at the resonant or at a frequency with orders of magnitude higher or lower than the cutoff frequency.

Problems

• 11.1. Design an inverting active low-pass filter to amplify the frequencies below 1kHz with gain of K = 150.

• 11.2. Design an inverting active high-pass filter to amplify the frequencies above 500Hz with gain of K = 100.

• 11.3. Design an active band-pass filter to amplify the frequencies between 500 and1000 Hz with gain of K = 200.

• 11.4. Design an active band-reject filter to eliminate the frequencies between 500 − 1000 Hz with gain of K = 200.

• 11.5. Determine the type of filter in the following circuit.

  

• 11.6. Determine if the following circuit can be a filter?

  

• 11.7. Determine the type of filter in the following circuit.

  

• 11.8. Design a second-order active low-pass filter to amplify the frequencies below 1 kHz with gain of K = 150. Sketch the circuit and determine the component values.

• 11.9. Design a second-order active high-pass filter to amplify the frequencies above 500 Hz with gain of K = 100. Sketch the circuit and determine the component values.

• 11.10. Design a second-order active band-pass filter to amplify the frequencies between 500 and 1000 Hz with gain of K = 200. Sketch the circuit and determine the component values.

• 11.11. Design a second-order active band-reject filter to eliminate the frequencies between 500 and 1000 Hz with gain of K = 200. Sketch the circuit and determine the component values.