“Band Pass filter is one which can pass only a specified band of frequencies. For example a band pass filter for woofers have the lower cutoff frequency as 200Hz and upper cutoff frequency as 2KHz, that is the mid range audio frequencies. I have made this bandpass filter which is suitable for woofers, that is the Mid Range speakers.
This bandpass circuit is an active filter circuit. This circuit is made using the Multiple Feedback technique with OPAMP. A single OPAMP section can make up the circuit for bandpass action. This technique is somewhat more advantageous than Sallen Key topology, since that would require two OPAMP sections to make up the filter.
We will proceed step by step, from design to simulation then finally testing the hardware.
- LM358 / JRC4558 / NE5532 or similar opamps
- 5 3.3k 0.25w resistor
- 3 4.7k 0.25w resistor (not value critical, anything from 1k-10k will work fine)
- 1 10k ohm potentiometer/trimmer
- 2 100nF ceramic capacitor
- 2 100uF, 16v capacitor
- Male berg headers
- Solid core wires
- PCB, Soldering materials, breadboard (optional)
- 9v/12v power supply”