In this note, we are going to learn About Public Address System or PA System and Block Diagram of Public Address System. Welcome to Poly Notes Hub, a leading solution for Diploma Engineering Notes for Polytechnic Students.
Author Name: Arun Paul.
What is Public Address System?
A Public Address System (PA system) is a collection of equipment designed to enhance sound for a large or dispersed audience. It often consists of microphones, amplifiers, loudspeakers, and other related equipment. Public areas with PA systems include stadiums, airports, train stations, shopping malls, schools, and offices. They are used to make announcements, broadcast music, provide emergency messages, and facilitate communication among big groups of people. PA systems can be wired or wireless, and their size and complexity vary according to the needs of the venue or event.
Block Diagram of Public Address System
The PA System consists several components which are listed below –
- Microphone: The microphone is an input device that converts sound waves to electrical signals. It records the voice or other audio sources and transmits the electrical signals to the mixer.
- Mixer: The mixer integrates audio signals from microphones, instruments, and other sources. It lets you to change the volume, equalization, and mixing of several audio sources before sending the combined signal to the amplifier.
- Voltage Amplifier: After the mixer combines the audio signal, the voltage amplifier raises the voltage level of the signal. The weak electrical signals are amplified in this stage so they can be processed further.
- Processing Circuit: A variety of parts, including equalizers, compressors, limiters, and effects processors, may be a part of the processing circuit. Depending on the needs, these parts modify the audio signal to improve its quality, change its tone, or add special effects.
- Driver Amplifier: The processed audio signal is received by the driver amplifier, which then amplifies it even more. It gets ready the signal so that enough power can be applied to the loudspeakers.
- Power Amplifier: The audio signal must be amplified by the power amplifier to a sufficient level for the loudspeakers to be powered. It increases the signal strength to a point where it can generate sound at the targeted loudness.
- Loudspeaker: The output device that transforms the electrical signal into sound waves once it has been amplified is the loudspeaker. When an electrical signal is received, a diaphragm vibrates, producing audible sound waves that travel through the atmosphere and are perceived by the audience.
Applications of Public Address System
Below we listed some applications of this system –
- Managing huge crowds at events, concerts, or sports stadiums by providing instructions and information.
- Announce arrivals, departures, and other crucial information at airports, train stations, and bus terminals.
- Broadcasting announcements, school events, and emergency protocols in educational facilities.
- Amplifying prayers, speeches, and announcements at churches, mosques, and temples.