Craft a 300-3kHz Bandpass Filter Circuit Diagram

Description

Human auditory perception primarily processes a limited range of sound frequencies, extending from 300Hz up to 3kHz. This particular frequency band is internationally acknowledged for the transmission of voice signals through communication networks. Consequently, this circuit’s primary application lies in utilizing this specific frequency spectrum, effectively eliminating frequencies below and above it, thereby ensuring clear and intelligible speech. The circuit comprises two active electronic components, second-order filters (designed for critical damping). The initial filter stage, employing IC1A, blocks low frequencies (under 300 Hz) utilizing a [high pass] configuration, while the second stage, IC1B, utilizing a [low pass] configuration, passes frequencies above 3kHz. This combination results in a total band-pass filter operating within the range of 300Hz to 3kHz. To achieve optimal filter performance, as with all filters, metal film resistors with a 1% tolerance and polystyrene capacitors are employed.

IC1 - TL072

The TL072 is a versatile, three-terminal operational amplifier widely utilized in analog circuit design. It’s renowned for its low noise, high input impedance, and good DC characteristics. This operational amplifier is frequently employed in filter circuits, instrumentation amplifiers, and other applications where precise amplification and signal conditioning are required. It’s a JFET-input operational amplifier, offering superior linearity and performance compared to bipolar-input devices.

Circuit diagram

Part List

All resistors are 1/4W 1-2%