This Bass Treble Tone Control Circuit using a Single Transistor BC547 is an easy tone control circuit.
Moreover, we can turn bass up or down and treble also in audio sound.
What is Bass Treble Tone Control Circuit:
Bass Treble Tone Control Circuit make treble go high by cutting sound below 500 Hz and when bass turn full it make sound below 100 Hz louder for strong bass.
Circuit Working:
Parts List:
| Components | Values | Quantity |
|---|---|---|
| Resistors | 10k CFR 1/4 W | 1 |
| 2.2M CFR 1/4 W | 1 | |
| 100k CFR 1/4 W | 2 | |
| Potentiometer 100k | 1 | |
| Potentiometer 250k | 1 | |
| Capacitors | Ceramic 1000pF | 2 |
| Ceramic 0.01µF | 2 | |
| Electrolytic 10µF 25V | 2 | |
| Semiconductors | Transistor BC547 | 1 |
Transistor BC547:
In this circuit BC547 does main job for handling frequency; also BC547 is normal NPN transistor and people use it many time in amplifier circuit.
Treble Control Part:
Treble control uses 100k pot and two 1000pF capacitors and we can turn this pot it changes treble in sound output.
Bass Control Part:
Bass uses 250k pot and 0.01uF capacitors and this pot is easy to turn and it makes bass tone go up or down.
Output Result:
Furthermore, circuit output goes direct to amplifier volume knob and that place normally control tone also.
Gain:
Here, the gain is almost same like unity when all knob are in middle; so sound does not get much louder or quiet when bass and treble both are in center.
Frequency Reply:
Also, when we turn treble and bass knob, circuit can cut sound at 15kHz or boost it near 15dB at 100Hz, this mean circuit can make high or low sound stronger or weaker.
Formulas:
Formulas for Bass Treble Tone Control Circuit with One Transistor:
Bass and Treble Control Tones:
This circuit have two filter parts one high pass filter for treble and other one is low pass filter for bass and we can use capacitor and resistor to change how much sound goes in each filter.
Also, this help adjust low and high sound focus.
Response Filter:
We used a simple formula for each filter stage and this formula is called a first-order RC filter.
High Pass Filter Treble:
Formula is:
fc = 1 / (2 * π * R * C)
where:
- fc cut off frequency in Hertz when signal starts to go down.
- π (pi) is around 3.14159.
- R is resistor value in ohm Ω.
- C is capacitor value in farad F.
Bass Low Pass Filter:
Low pass filter uses same formula but we choose lower fc to hit bass sound.
Important Things:
Hence, the above formula give close idea of cut off frequency but real filter does not always match exact because circuit parts affect each other.
Furthermore, the potentiometer changes the resistance value, so we can adjust the cutoff frequency and control the bass or treble more effectively.
Also, changing fc help change how bass and treble sound in audio.
How it is Build:
To build a Bass Treble Tone Control Circuit using a Single Transistor follow the connections steps below:
Placing the BC547 Transistor:
- First, put BC547 transistor on PCB or on breadboard and check which pin is emitter, base and collector.
Base Resistor:
- After that, connect a resistor from the transistor base to the power source
- Also, if the resistor value is not fixed, we can choose it according to the transistor operation and circuit requirements.
Treble Control Part:
- Then connect 100k potentiometer to transistor base.
- Middle pin of this pot connects to collector and one side to base and other side to ground; also both ends of 100k pot connect to two 1000pF capacitors.
Bass Control Part:
- Now connect 250k potentiometer to transistor base too.
- Middle pin of pot goes to collector with one side to base and other side to ground; also put one 0.01uF capacitor on each side of this pot.
- Next, connect power positive and negative to right place in the circuit and be sure voltage is okay for BC547 transistor.
Output Connection:
- Also, collector output from transistor goes to input of power amplifier or another audio part.
Testing and Tuning:
- Turn ON the circuit and check output using speaker or oscilloscope and sound source.
- If required, change 100k and 250k pots to adjust treble and bass.
Important Note:
- To conclude maybe we need to find best resistor value for base and other parts; also it depend on parts we use and for our goal.
- Before turning ON circuit double check all connection are correct
Conclusion:
To conclude, the Bass Treble Tone Control Circuit using a single BC547 transistor is a simple and low cost way to adjust audio tones.
Also, with just one transistor, a few resistors, capacitors and potentiometers this circuit allows control over bass and treble frequencies.
Hence, it is easy to build and useful for basic audio projects or learning purposes.