Headphone Amplifier Circuit using Transistors make weak sound strong so headphones work well, also this circuit is useful when sound is direct from source which is not loud or clear.
In addition, in this post we will talk about small 3V transistor amplifier for better sound.
Circuit Working:
Parts List:
| Components | Values | Quantity |
|---|---|---|
| Resistors (All resistors are 1/4 watt unless specified) | 10k | 1 |
| 100k | 1 | |
| 68k | 1 | |
| 1.5k | 1 | |
| 3.3k | 1 | |
| 330Ω | 1 | |
| 4.7k | 1 | |
| 2.2k | 1 | |
| Capacitors | PPC 1µF | 1 |
| Electrolytic 100µF 25V | 1 | |
| Electrolytic 470µF 25V | 1 | |
| Semiconductors | Transistor NPN BC547 | 2 |
| Transistor PNP BC557 | 1 | |
| On / Off Switch | 1 | |
| Headphone | 1 | |
| 3V Battery | 1 |
To begin with, circuit uses 3 transistors Q1 BC547, Q2 BC547, Q3 BC557 for small signal boost and audio is in through C1 1µF to Q1 and work as preamp.
Then Q2 and Q3 is in push-pull which gives more gain and Q1 is voltage amp, Q2 is driver and Q3 is power amp for headphones.
After that C2 and C3 help signal pass and cut noise and R1 to R8 set bias and gain.
3V battery and S1 switch powers the circuit and then output goes to headphones with clear sound clear and with no distortion.
How to Build:
To build a Headphone Amplifier Circuit using Transistors follow the below mentioned steps:
- First, connect base of Q1 to one end of R1 and R1 goes to C1 and C1 goes to audio input and connect R2 between base of Q1 and GND.
- Next, connect emitter of Q1 to GND through R6, connect collector of Q1 to base of Q2 and also connect collector of Q1 to positive supply through R4 and R5.
- After that, connect collector of Q2 to base of Q3 and to one end of R7 and R7 goes to positive supply and connect emitter of Q2 to collector of Q3.
- Then connect one end of R3 between the junction of R1, R2 and base of Q1 and the other end to collector of Q3.
- Also, connect positive of C2 between R4 and R5 and connect negative of C2 between R3 and collector of Q3 and also connect emitter of Q3 to positive supply of 3V.
- Now connect collector of Q3 to one end of R8 and R8 goes to one end of the headphone and the other end of the headphone goes to GND.
- Further, connect positive of C3 to positive supply and negative of C3 to GND and then connect S1 between positive supply of the circuit and +3V battery and connect negative of 3V battery to GND.
Conclusion:
To conclude, Headphone Amplifier Circuit using Transistors is cheap, easy to make and portable and it is good for DIY audio, small projects or as a preamp.