Wireless transmissions require modulated waves to be sent over long distances through air. The output of an audio power amplifier ranges from a few milliwatts (like in headphone amplifiers) to thousands of watts (like power amplifiers in Hi-Fi/Home theatre systems). The amplifiers used in speaker driving circuitries of televisions, mobile phones etc. This type of power amplifiers are used for increasing the magnitude of power of a weaker audio Signal. Types of Power Amplifiersĭepending on the type of output device that is connected, power amplifiers are divided into the following three types: Finally, the signal is passed through a power amplifier and the output from power amp is fed to a speaker. Then the signal is passed through a tone and volume control circuit, which makes aesthetic adjustments to the audio waveform. So, first it is pre-amplified, where its voltage and current are increased slightly. The magnitude of signal from the microphone is not enough for the power amplifier. In this case, a microphone is used as an input source. You can observe the block diagram of an audio amplifier and the usage of power amplifier below. So, instead of directly passing the raw audio/RF signal to the power amplifier, it is first pre-amplified using current/voltage amplifiers and is sent as input to the power amp after making necessary modifications. The input signal to a power amplifier needs to be above a certain threshold. Unlike voltage/current amplifiers, a power amplifier is designed to drive loads directly and is used as a final block in an amplifier chain. The power of the input signal is increased to a level high enough to drive loads of output devices like speakers, headphones, RF transmitters etc. For more information on different types of amplifiers: Different Types and Applications of Amplifiers What is a Power Amplifier?Ī power amplifier is an electronic amplifier designed to increase the magnitude of power of a given input signal. In this article we will learn about power amplifiers in detail.
It takes in a weak electrical signal/waveform and reproduces a similar stronger waveform at the output by using an external power source.ĭepending on the changes it makes to the input signal, amplifiers are broadly classified into Current, Voltage and Power amplifiers. An amplifier is an electronic device used to increase the magnitude of voltage/current/power of an input signal.