This proposed 7 watt amplifier circuit is like an efficient audio booster. It is easy to construct and also works like a charm when amplifying audio signals or increasing the feeble output of a small transistor radio.
Figure below shows the audio power amp with comprises the LM383 amplifier. This part is the most crucial part of the portable amp. It is designed for low-impedance loads like a 4 ohm speaker and has extremely low distortion.
Furthermore, the LM383 is activated from supply voltages ranging from 5 to 20 V.
Because the device is custom-made for automotive applications, using 12 V would be just nice. Additionally, the operating cost for this op-amp is incredibly low – 3 dollars per unit.
The portable 7 watt amplifier circuit shown in this project was constructed for a common-purpose universal amplifier.
It can be applied for various applications. Just like a speaker load for a transistor radio, the switch S2 is capable of toggling the amp’s input impedance between just 16 ohms (low) to 10k ohms (high).
It is possible to switch the amp’s output from the internal 4-ohm speaker to an external speaker.
If you fit a metal-horn paging speaker, you’re in for deafening sound from the amplifier. Conveniently, you can fir this amp with a car battery and used for automotive purposes.
How to Build
This amplifier can be easily constructed. The circuit is quite small and can be made on a perfboard and enclosed within a hard plastic case.
It is important to remember to mount the IC LM383 on heatsink with a minimum area of 4 in2.
Using just scrap aluminium, the heat sink can be constructed. Or, you can simple purchase one from the local electronic store.
After that, you just need to mount the speakers, attach the I/O jacks and fix the volume control (R4) at points on the enclosure which work for you.
For whichever arrangement you choose, it is fundamental that you permit sufficient open space in front of the speaker for the sound to travel without any restrictions.
You may supply eight C-cell batteries to power up this 7 watt amplifier circuit. For more tidiness, you can prepare a battery holder which will contain the C-cell batteries and makes replacement easy. For portability, just fasten a simple handle and you’re good to go.
For the complete datasheet, please refer to the following article: