The objective of this report is to illustrate the entire process of bringing an audio amplifier from a circuit diagram to a finished, working product. The basis of the amplifier will be the LM386 chip and as such, this will be looked at in further detail along with other technical features of the project. Aims and Objectives The overall objective of this project is to design and build the circuit for a stereo output audio amplifier whilst ensuring a high sound quality at all input frequencies and volume settings.
The housing for the circuitry and speakers must also be considered, it should be strong enough to withstand being moved about and sturdy as to ensure that it doesn’t rattle when it is playing music. It should appear professionally made and with an interesting and unique design. It should be simple to use allowing it to be enjoyed by all consumers, of all ages, as well as having a high quality sound output with minimal static, especially at the more common ranges of frequencies. The speaker system must have a wide range in volume, which must be easily controlled.
Portability is not an issue as this is not to be designed as a portable amplifier, rather a semi-permanent loudspeaker system. The product is to have two speakers set up in stereo, with the input to be provided by an MP3 device. The two speakers will have an internal resistance of 8 ohms each, with each wired to either the left or right feed of the audio from the MP3 device jack. The amplifier will have a gain of 20db. The volume controls will be an analogue system using a potentiometer connecting both of the two speaker systems together to ensure consistency throughout the listening experience.
The system will be powered by one 9 volt battery which will be easily accessible for ease of access. To ensure that the power source does not drain over time, a switch will be connected to enable the whole system to be turned on and off. The housing for the speakers and for the circuitry will be of a unique design whilst still enabling for practicality in terms of connecting the MP3 device, volume control and powering the amplifier system on and off. Specifications Switch to turn the amplifier on and off Volume control which will control both speakers simultaneously Power supply from 9 volt battery Gain of 20db