The first audio amplifier was designed in the year 1909 by Lee De Forest when he developed the triode vacuum tube. The triode was a three terminal device with a control grid, which is used to modulate the electrons flow from the filament to the plate. This amplifier is mainly used to design the first AM radio. First audio amplifiers were based on valves which are called as vacuum tubes.But, present audio amplifiers are based on different types of transistors like FETSs, MOSFETs and BJTs. At present, there are still select valve sound and tube based amplifiers. In the year 1960, the audio amplifier which is based on transistors became hands-on with a low cost transistors in the wide range of availability.
What is an Audio Amplifier?
An audio amplifier is an electronic device, that is used to increase the amplitude strength of audio signals that flow through it. These amplifiers strengthens low-power audio signals to a level which is apt for driving loudspeakers. The audio amplifiers i/p signal can measure only a few100mwatts, but its o/p may be 10 to 1000’s of watts. The design parameters of an audio amplifier include frequency response, noise and distortion and gain.
Classification of Audio Amplifiers
There are various types of audio amplifiers are classified into different types based on o/p power, gain, nominal gain, max supply voltage, type of packaging and number of channels The basic sizes of gain are 20dB, 26dB, 30dB, 36dB & 48dB and 115dB gain amplifiers also we can carry. The number of audio amplifiers have 1 and 10 channels, whereas the most used audio amplifiers have 1,2 or 4 channels.
The future audio amplifiers are programmable audio amplifiers which are used to design a mini audio amplifier, audio amplifier IC, home audio amplifier, digital audio amplifier, car audio amplifier, low power audio amplifier, Inline audio amplifier, TV audio amplifier, stereo audio amplifier or PC audio amplifier
22W Audio Amplifier Circuit
The 22W audio amplifier circuit is very simple to build and low cost. This audio amplifier circuit is used in a car audio system as a booster, home theater systems, amplifier for satellite speakers and amplifier for computer speakers. This audio amplifier circuit uses 22W and it is quite compact
The Required Components
The required electrical and electronic components of 22W audio amplifier circuit are listed below.
- C1, C2- 10uf 25V electrolyte capacitors
- U1- TDA1554 2-channel audio amp chip
- MISC- Heat sink for U1, RCA jacks, binding posts and Boar and Wire
The 22W audio amplifier circuit works with 12volts power supply which is shown below. A transformer is used to convert from 230 volts to 12 volts from the mains. Bridge rectifier is designed by four diodes namely IN4003 or IN4007 and it converts AC to DC. The filtering capacitor reduces the ripple and gives the smooth DC voltage. The power supply circuit is very easy to build. For better performance i/p voltage must be greater than 12volts at pin1 of the LM7812IC for protecting from overheating.
- The audio amplifier circuit shown in the above is based on the TDA1554 IC. The TDA 1554 is an integrated audio amplifier that can deliver 22 watts of audio output power
- The 22W audio amplifier circuit includes with 4 ohm speakers, but 8 ohm units will do.
- This circuit wastes 28 watts of heat roughly, so a good heat sink is mandatory
- The chip in this circuit must work in cool enough to touch with the appropriate heat sink which used.
- The above circuit works with 12V at about 5 Amps at full volume. When the lower volumes consume less current, then it will generate less heat.
- PCB (printed circuit board) is used and maintain the lead length short.
The design parameters of the audio amplifier circuit are gain, noise, distortion and frequency response. These parameters are independent and when the gain the amplifier increases, then the noise and distortion also increase. The negative feedback of the amplifier reduces the gain and distortion. Most of the audio amplifiers are linear and operates in class AB
Applications for Audio Amplifiers
The applications o audio amplifiers mainly involves in home audio systems, concert & theatrical sound reinforcement, public address systems. The sound card in a PC, every home theatre system and stereo system comprises of many audio amplifiers. Other applications of audio amplifiers include instrument amplifiers like portable consumer goods like toys, games, amateur mobile radio, guitar amplifiers, etc.
Thus, this is all about 22W audio amplifier circuits and its working. We hope that you have got a better understanding of this concept. Furthermore, any queries regarding this topic, please give your feedback by commenting in the comment section below. Here is a question for you, what is the main function the audio amplifier?