Browse Definitions :
Definition

amplifier

What is an amplifier?

An amplifier is an electronic device that increases the voltage, current, or power of a signal. Amplifiers are used in wireless communications and broadcasting, and in audio equipment of all kinds. They can be categorized as either weak-signal amplifiers or power amplifiers.

Types of amplifiers

  • Weak-signal amplifiers are used primarily in wireless receivers. They are also employed in acoustic pickups, audio tape players, and compact disc players. A weak-signal amplifier is designed to deal with exceedingly small input signals, in some cases measuring only a few nanovolts (units of 10-9 volt). Such amplifiers must generate minimal internal noise while increasing the signal voltage by a large factor. The most effective device for this application is the field-effect transistor. The specification that denotes the effectiveness of a weak-signal amplifier is sensitivity, defined as the number of microvolts (units of 10-6 volt) of signal input that produce a certain ratio of signal output to noise output (usually 10 to 1).
  • Power amplifiers are used in wireless transmitters, broadcast transmitters, and hi-fi audio equipment. The most frequently-used device for power amplification is the bipolar transistor. However, vacuum tubes, once considered obsolete, are becoming increasingly popular, especially among musicians. Many professional musicians believe that the vacuum tube (known as a "valve" in England) provides superior fidelity.

Two important considerations in power amplification are power output and efficiency. Power output is measured in watts or kilowatts. Efficiency is the ratio of signal power output to total power input (wattage demanded of the power supply or battery). This value is always less than 1. It is typically expressed as a percentage. In audio applications, power amplifiers are 30 to 50 percent efficient. In wireless communications and broadcasting transmitters, efficiency ranges from about 50 to 70 percent. In hi-fi audio power amplifiers, distortion is also an important factor. This is a measure of the extent to which the output waveform is a faithful replication of the input waveform. The lower the distortion, in general, the better the fidelity of the output sound.

This was last updated in December 2021

Continue Reading About amplifier

Networking
  • WAN (wide area network)

    A wide area network (WAN) is a geographically distributed private telecommunications network that interconnects multiple local ...

  • SD-branch

    SD-branch is a single, automated, centrally managed software-centric platform that replaces or supplements an existing branch ...

  • network operating system (NOS)

    A network operating system (NOS) is a computer operating system (OS) that's designed primarily to support workstations, PCs and, ...

Security
  • Cloud Security Alliance (CSA)

    The Cloud Security Alliance (CSA) is a nonprofit organization that promotes research into best practices for securing cloud ...

  • quantum supremacy

    Quantum supremacy is the experimental demonstration of a quantum computer's dominance and advantage over classical computers by ...

  • antivirus software (antivirus program)

    Antivirus software (antivirus program) is a security program designed to prevent, detect, search and remove viruses and other ...

CIO
  • transaction

    In computing, a transaction is a set of related tasks treated as a single action.

  • lean management

    Lean management is an approach to managing an organization that supports the concept of continuous improvement, a long-term ...

  • device ID (device identification)

    A device ID (device identification) is an anonymous string of numbers and letters that uniquely identifies a mobile device such ...

HRSoftware
  • talent pool

    A talent pool is a database of job candidates who have the potential to meet an organization's immediate and long-term needs.

  • diversity, equity and inclusion (DEI)

    Diversity, equity and inclusion is a term used to describe policies and programs that promote the representation and ...

  • passive candidate

    A passive candidate (passive job candidate) is anyone in the workforce who is not actively looking for a job.

Customer Experience
  • product-qualified lead (PQL)

    A product-qualified lead (PQL) is an individual or business that experienced value from using a product as a result of a free ...

  • marketing-qualified lead (MQL)

    A marketing-qualified lead (MQL) is a website visitor whose engagement levels indicate they are likely to become a customer.

  • customer success

    Customer success is a strategy to ensure a company's products are meeting the needs of the customer.

Close