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What are the Functions and Characteristics of Amplifier PCB?

Amplifier circuit boards play a crucial role in the designing of some electronic devices. These boards are often regarded as the heart of an amplifier. Amplifiers are useful in sound reproduction. Therefore, you will find amplifier PCBs in devices that generate sounds. For instance, a loud speaker features an amplifier PCB. Therefore, we will be discussing the amplifier circuit board in this article.

What is an Amplifier PCB?

An amplifier PCB is a circuit board that generates an enhanced version of an input signal that is fed into input terminals. This PCB is the building block of an amplifier. Typically, this type of PCB features some electronic components that accept a signal. Also, these components enhance the strength of an amplifier by passing the signal via a transistor or tube.  

PCBs are in different capabilities and sizes. However, they feature components soldered to a substrate. The most important part of the amplifier PCB is the substrate. The wafer on which the components sit is made of a resin reinforced with fiberglass.

Amplifier PCBs feature several electronic components. However, the actual amplifier is a single component. Furthermore, this board houses several capacitors and resistors that offer different functions. Also, it will feature output and input terminals for the amplified signal and original signal respectively.

Technically, many boards feature large heat sinks connected to the amplification component. An amplifier circuit board can be large or small. This depends on the application. Several portable headphone amplifiers are small. The circuit boards can measure a few square inches. However, amplifier PCBs for a professional audio or a large audiophile home amplifier can be very large. This PCB can measure more than 100 square inches.

Most times, amplifier PCBs lack one essential component which is the power supply. For a battery powered amplifier, the battery provides the power. Also, there is no need for intervening circuitry. Many small amplifiers integrate an external power supply. There are majorly two types of amplifier circuit boards. These are the audio and power amplifiers.

Difference between Amplifier PCBs and Normal PCBs

An amplifier PCB is different from a normal PCB. The manufacturing of a normal PCB requires the use of through-hole technology. This technology helps to mount PCB components and drill many holes. Also, another technology commonly used is the surface mount technology.

However, the manufacturing process of an amplifier PCB is different. This PCB is usually fabricated via a schematic capture. A software known as EasyEDA helps to place components. Also, the complexity of the circuit determines the physical aspects of the board.

Some factors are very important when placing components in an amplifier board. These are thermal and geometry factors. Also, in an amplifier PCB, the power output and input functions in response with the resistance of the transistors.

The dielectric constant of this PCB is better than that of a normal PCB. However, these two PCBs require the use of schematic diagrams in their design. Also, a normal PCB can be manually designed via a Photomask.

Functions of Heat Sinks in Amplifier PCBs

Amplifier PCBs feature heat sinks that help to dissipate heat generated during operation. Also, these heat sinks are usually made of aluminum materials. This is because these materials feature high conductivity levels. Also, the ability of aluminum to withstand abrasion and corrosion makes it a better option.

These heat sinks work with the help of thermovia and copper coins. Also, thermovia are holes located below heat-generating components. The heat sink is often mounted on the amplifier PCB. Also, the mounting of these sinks requires some components.

When mounting an amplifier PCB, components line solder pins and shur-lock tabs are essential.  Heat sinks play a crucial role in amplifier boards. These heat sinks enhance thermal management in amplifier PCBs.  Thermal management is crucial in amplifier boards.  

Uses of Amplifier PCB

Amplifier PCBs serve several purposes. These circuit boards are ideal for use in several applications. Also, these boards are the major point of operation when transforming analog signals to digital signals. First of all, the signals need to be amplified.

  • An amplifier PCB helps to enhance the amplitude of signals. While doing this, it maintains other aspects like frequency.
  • This PCB can transform analog signals to square waves. Therefore, it takes advantage of the high input saturation.
  • An amplifier circuit board has a high voltage and high output resistance. Therefore, this allows it to offer adequate output to drive loudspeakers.
  • This board helps to identify metal fatigue. Also, they help in ultrasound scanning and ultrasonic cleaning.
  • An amplifier board with a constant gain between AC and DC is useful in oscilloscopes.
  • There is not much gain due to the low input resistance of this board. Therefore, it functions as a buffer between the receiver and the circuitry. Also, it prevents unwanted signals.

Characteristics of an Amplifier PCB

Amplifier circuit boards possess the following characteristics:

High input impedance

This is very important at the input signal as it helps the voltage drop entirely on the amplifier. There will be no voltage drop across the amplifier for low input impedance. Therefore, amplifier circuit boards require low impedance materials. Also, high input impedance is crucial to avoid loading. The operational amplifier would absorb large amounts of current if it had low input impedance.

Limited bandwidth

It is crucial to consider a bandwidth that suits the frequency it should amplify when designing amplifiers. There will be loss of signal frequency if there is a narrow bandwidth. Meanwhile, there may be noise if the bandwidth is very wide.

High open-loop gain

This is the ability of an amplifier to enhance the power of the signal. This can be measured between the input and output ports when the circuit has no feedback. Also, it is very possible to get many feedback levels when there are high open loop gains.

Low output impedance

The signal amplifies when the voltage drops across the operational amplifier. You can lose signal across the device the amplifier feeds.


Amplifier PCBs have great uses and advantages. In this article, we have provided detailed information about amplifier circuit boards and what they do.