During testing, at the output also, a speaker is not used as a load as the speaker is resistive as well as inductive. So, the function generator can be used as input source for testing the audio amplifier circuit. Any audio signal is also basically a sine wave so a function generator can be used instead of using a microphone or actual audio source. The function generator is used to generate a sine wave of constant amplitude and frequency. As the resistor value is decreased, the bass gets more amplified compared to treble in the audio.įor the testing of the amplifier circuit, the function generator is used as the input source. The bass boost of the amplifier can be varied by adjusting the variable resistor RV3. So the bass frequency signals are more amplified than high frequency signals. In fact, rather than boosting the low frequency signals, this RC network actually reduces the gain at high frequency.

So high-frequency signals are less amplified due to reduced gain. Therefore, there is more feedback to the output and this reduces the gain of the circuit. So instead of 10K, the equivalent resistance is reduced to 6K ohms (15K || 10K). The RC network effectively act as a 10K ohms resistor which is in parallel to the internal 15K ohms resistor of the IC.

At High frequency, the capacitor C6 has very low reactance and it will act as a short circuit. In this case, the amplifier behaves as if the RC network is not present.

At low frequency, the capacitor C6 has high reactance (Xc = ½*Pi*f) so the external RC network act as an open circuit.

What is bass boost