What is an amplifier?

Electronic device that increases the voltage, current or power of a signal.
Kind of uses
1. Wireless Communication
2. Acoustic pickups
3. Audio equipment
4. Boardcasting
Classification
1. Weak-signal amplifier
  1. Wireless recivers
  2. Commonly found in FET
2. Power amplifier
  1. Transmitters
  2. Commonly found in bipolar transistor
Characheristic
1. Gain
  1. It's the increase in signal power
  2. Symbolized with letter 'A', and expressed in decibel
2. Bandwidth
  1. Range of frequencies for which the amplifier gives "satisfactory performance"
3. Efficiency
  1. Measure of how much of the powersource is usefully applied to the amplifier's output
4. Cascade application
  1. Used when a single-stage amplifier is not sufficent for a particular purpose
  2. This configuration is created by connecting 2 or more amplifiers one after another
  3. The total gain is the product of each gain
Inconvenience
1. Noise and distorsion
  1. Unwanted signal that degrade the desired signal content in the system
  2. It's found in 2 different types, the first it the noise generated by the system itself and the second is the noise recived in the input
  3. To avoid these problem a general techinque called negative feedback is used.
    1. Portion of the output is fed back and compared with the input signal to stabilise amplification and reduce distortion

Resumo de Recurso

	Criado por Claudio Salin quase 6 anos atrás