What is an amplifier?

This is an electronic device which heightens the power, current or voltage of a signal. Audio amplifiers vary in capacity, type and uses. 

They are used for

  • Audio equipment and musical instruments such as guitar.
  • Broadcasting
  • Wireless communications

Amplifiers used in wireless communications might not be compatible with those used for audio equipment or musical instruments. The size of an amplifier sometimes limits its usage to specific areas. Unbiased monoprice tube amp review evaluates an amplifier in relation to the capacity, usefulness and price.

Types of amplifiers

Weak signal amplifiers

These are amplifiers generally employed in wireless communication. They are installed in wireless receivers. They are also used in audio tape players, acoustic pick-ups and compact disc players.

This amplifier is built to handle very little input signals and sometimes desks with signals as low as just a few nanovolts. Weak signal amplifiers are able to produce just the slightest noise internally while remarkably heightening the signal voltage. The important consideration in weak signal amplifiers is the sensitivity which debited the effectiveness of the amplifier.

Power amplifiers

These amplifiers are majorly used HiFi audio equipment, wireless transmitters and broadcast transmitters. Power amplifiers are considered based on their power output and efficiency.

  • HiFi audio equipment: distortion is an important factor. Lower distortion implies better sound output.
  • Wireless communications: efficiency varies from a 50% to a 70% to range. The same is applicable to broadcasting transmitters.
  • Audio applications: efficiency varies from a 30% to a 50% range

Properties of an amplifier

  • Bandwidth. This is the breadth of useful range of frequency.
  • Gain. This is the ratio of the magnitude of output signals to the magnitude of input signals.
  • Efficiency. This is the ratio of the power of output of the amplifier to the total power consumed by the amplifier.
  • Noise. This is the estimation of unwanted noise included in the output of the amplifier. An amplifier is more effective with minimal noise output.
  • Linearity. This is the range in which the amount between the output and input amplitudes is equal for high amplitude and low amplitude input.
  • Output dynamic range. This is the ratio of the highest output level to the lowest output level.
  • Stability. This is when the amplifier is able to avoid self oscillating.
  • Slew rate. This is the max rate of output change.

Amplifiers are often described based on the properties of outputs, inputs and relation. All amplifiers are comprised of at least one active device such as transistor or vacuum tube. Weak signal amplifiers consist of vacuum tubes while power amplifiers consist of transistors. 

Amplifiers are mostly built to be linear. This means that they produce consistent gain for any average output signal and input level. In cases whereby the gain of an amplifier isn’t linear, it is very possible for the output signal to become distorted. Despite this, there are some exceptional cases whereby variable is actually put into good use.

When buying an amplifier, one of the important factors to consider is the use of the amplifier. Amplifiers most times can’t be interchanged in terms of usage. An amplifier used for certain equipment might not be compatible for others; hence that should be kept in mind 


Amplifiers are used to increase input signals into higher output signals. The output of an amplifier is mixed with noise which might be a disturbance if too prominent. A good amplifier is characterized with good efficiency and minimal noise. The efficiency of an amplifier varies based on the category of the amplifier.

Amplifiers are used in high fidelity (HiFi) stereo equipment, guitar, digital equipment, micro computers, radio transmitters and receivers, television transmitters and receivers, and other equipment.


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