Project Amplifiers Dalla

•RANJIT SINGH •MANDEEP KUMAR •MANPREET SINGH •JASWINDER SINGH

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Definition General characteristics of amplifiers 2.1 Gain 2.2 Output dynamic range 2.3 Bandwidth and rise time 2.4 Settling time and aberrations 2.5 Slew rate 2.6 Sine wave distortion

2.7 Noise 2.8 Efficiency

Generally, an amplifier is any device that uses a small amount of energy to control a larger amount of energy. In popular use, the term today usually refers to an electronic amplifier, often as applied to audio applications.

1 Gain 2 Output dynamic range 3 Bandwidth and rise time 4 Settling time and aberrations 5 Slew rate 6 Sine wave distortion 7 Noise 8 Efficiency 9 Linearity

Th e inreas es in th e signal level is call ed t he gain . Th is is us ually m eas ured in decibels (dB ). Mat hem at ically speakin g, t he g ain is e qual to the out put level divi ded by t he in put level.

Output dynamic range is the range, usually given in dB, between the smallest and largest useful output levels. Since the lowest useful level is limited by output noise, this is quoted as the amplifier dynamic range.

The bandwidth (BW) of an amplifier is usually defined as the difference between the lower and upper half power points. This is therefore also known as the −3 dB BW. Bandwidths for other response tolerances are sometimes quoted (−1 dB, −6 dB etc.).

Time taken for output to settle to within a certain percentage of the final value (say 0.1%). This is usually specified for oscilloscope vertical amplifiers and high accuracy measurement systems.

Slew rate is the maximum rate of change of output variable, usually quoted in volts per second (or microsecond).

The properties of amplifier circuits distort the signal This distortion comes in several forms including harmonic distortion and intermodulation distortionThis is a useful way of characterizing an amplifier because any signal can be broken down into a series of sine and cosine waves via the fourier transform Thus the response of an amplifier to an arbitrary signal can be analyzed provided one knows the response

This is a measure of how much noise is introduced in the amplification process. Noise is an undesirable but inevitable product of the electronic devices and components. It is measured in either decibels or the peak output voltage produced by

Efficiency is a measure of how much of the input power is usefully applied to the amplifier's output. Class A amplifiers are very inefficient, in the range of 10–20% with a max efficiency of 25%. Modern Class AB amps are commonly between 35–55% efficient with a theoretical maximum of 78.5%. Commercially available class D amplifiers have reported efficiencies as high as 97%. The efficiency of the amplifier limits the amount of total power output that is usefully available. Note that more efficient amps run much cooler, and often do not

An ideal amplifier would be a totally linear device, but real amplifiers are only linear within certain practical limits. When the signal drive to the amplifier is increased, the output also increases until a point is reached where some part of the amplifier becomes saturated and cannot produce any more output; this is called clipping, and results in distortion. Some amplifiers are designed to handle this in a controlled way which causes a reduction in gain to take place instead of excessive distortion; the result is a compression effect, which (if the amplifier is an audio amplifier) will sound much less unpleasant to the ear. For these amplifiers, the 1dB compression point is defined as the input power (or output power) where the gain is 1dB less than the