How Amplifiers Work
Stereo components or musical instruments are typically referred to as “amplifiers.”
However, this is just a sliver of what is available in the world of audio amplifiers.
Amplifiers are literally all around us.
Televisions, laptops, CD players and other devices that require a speaker to produce sound will all have them on board.
It’s fascinating to see how sound works.
Vibrations in the atmosphere cause air molecules to flow in and out of the vicinity of the source of the vibrations.
The pulse of the vibration is carried through the air by these air particles, which in turn move the air particles around them.
These changes in air pressure are picked up by our ears and processed by our brains as electrical signals.
The fundamentals of electronic sound equipment are the same.
It uses shifting electric currents to represent sound.
As a rule of thumb, this type of sound reproduction involves three steps:
An electrical signal is generated by the movement of a microphone diaphragm in response to sound waves.
The sound wave’s compressions and decompressions are reflected in the electrical output.
For example, a recorder may encode this electrical signal as magnetic impulses on tape or grooves on a record.
As an electrical signal, this pattern is used to drive a speaker cone back and forth in a player (like a tape deck).
In this way, the microphone captures the original air pressure variations.
As you can see, the majority of the system’s primary components are all translators
They convert the signal from one form to another.
To recapture the original physical sound wave shape, the sound signal is converted back to its original form.
The microphone diaphragm must be exceedingly sensitive in order to register all of the tiniest pressure fluctuations in a sound wave.
In other words, it is extremely light and goes quite quickly.
As a result, the microphone generates a relatively low amount of electrical current.
Since it is strong enough to be used in a recorder and can be simply communicated through wires, this is suitable for the majority of the process steps.
Final phase in process is more difficult: pushing speaker cone back and forth.
In order to achieve this, you must increase the current of the audio stream while maintaining the same pattern of charge variation.
This is the amplifier’s job.
The audio signal isn’t changed in any way; it’s simply amplified.
Learn more about what amplifiers do and how they work in this article!
There are hundreds of tiny parts in an amplifier, but you can see how it works by examining its most basic components.
Here we’ll take a closer look at the fundamental components of amplifiers.
Pump it Up
An amplifier’s fundamental principle is this:
A lower current is used to alter a bigger current, as seen in the figure.
An amplifier’s job is to amplify a weak audio signal into a signal strong enough to drive a speaker, as we saw in the previous section.
When you examine the amplifier as a whole, this is a fair description, but the amplifier’s internal processes are a little more complicated.
In reality, the amplifier transforms the input signal into an entirely different output signal.
These two signals can be viewed as distinct circuits.
Power is drawn from a battery or an electrical outlet to power the amplifier’s output circuit.
With home alternating current (AC), the power supply will convert it into direct current (DC), which always travels in the same direction regardless of what direction it is flowing.
In addition, the power supply evens out the current to provide a signal that is perfectly even and uninterrupted.
Load (the amount of work done by the output circuit) is represented by the speaker cone being moved by the signal.
Recorded audio or a microphone’s electrical signal are inputs to the input circuit.
The output circuit is being modified by its load.
Recreates voltage variations in the original audio signal by altering resistance in the output circuit.
The original audio signal cannot handle the load in most amplifiers.
First, a pre-amplifier boosts the signal, resulting in a more powerful output signal for the power amplifier.
Preamplifiers and amplifiers both operate in essentially the same ways:
The power supply’s output circuit is subjected to fluctuating resistance from the input circuit.
In order to progressively increase the output voltage of an amplifier system, many preamplifiers may be employed.
What is the amplifier’s role in this process?
An amplifier is a complex mess of wires and circuitry components that you’ll find if you look inside.
To ensure that the audio stream is appropriately portrayed, the amplifier requires a complex set-up.
Controlling a high-quality output necessitates extreme precision.
You’ll find a lot of electronic components within an amplifier.
Large transistors form the heart of the design.
The heat sink is responsible for removing the heat generated by the transistors.
Even while each component of an amplifier is critical, it is not necessary to dissect each one in order to gain a thorough understanding of how an amplifier works.
The amplifier’s operation relies on a small number of critical components.
This basic amplifier design will be examined in greater detail in the following section.
The transistor is a common amplifier component.
Semiconductors, materials with varied electrical conductivity, make up the bulk of a transistor’s components.
One impurity (an atom from a different material) is typically added to a poor conductor, such as silicon, to create a semiconductor.
Doping is the process of adding contaminants.
There are no free electrons in pure silicon, because all of the silicon atoms are perfectly bound to their neighbors.
Additional atoms in doped silicon upset the balance, either by adding free electrons or producing holes in which electrons can travel.
It is possible to increase the conductivity of a material by adding one or both of these components.
Extra electrons are a distinguishing feature of N-type semiconductors (which have a negative charge).
Extra holes abound in P-type semiconductors (which have a positive charge).
Look at a transistor amplifier with a bipolar-junction base.
An n- and p-type semiconductor are sandwiched between two layers of n-type semiconductors in this type of transistor
As depicted in the diagram below, this structure is best depicted as a bar (the actual design of modern transistors is a little different).
The emitter is the first n-type layer, the base is the p-type layer, and the collector is the second n-type layer.
The transistor’s emitter and collector electrodes are linked to the output circuit (the circuit that drives the speaker).
The emitter and base are connected to the input circuit.
There are free electrons in the n-type layer that naturally want to fill holes in the p-type layer.
A lot of free electrons compared to holes means that the holes fill very quickly.
Depletion zones form at the interface of n-type and p-type material.
There are no free electrons or empty spaces for electrons, therefore charge cannot flow in a depletion zone. The semiconductor material returns to its previous insulating state.
Voltage differences between emitter and collector are much greater when the depletion zones are large, yet relatively little charge can flow from emitter to collection.
Boosting the Voltage
Increasing the voltage on the base electrode when depletion zones are large is a good idea.
This electrode’s voltage is directly influenced by the amount of current flowing through it.
A positive charge on the base electrode attracts electrons from the emitter while the input current is flowing.
As a result of this, the depletion zones get smaller.
The transistor becomes more conductive when depletion zones are eliminated.
The voltage at the base electrode determines the size of the depletion zones and thus the conductivity of the transistor.
As a result, the collector electrode’s output current fluctuates in response to the base electrode’s variable input current..
The speaker is powered by this signal.
There are several transistors in an amplifier, each of which constitutes a “stage.”
To drive the speaker, an amp will often contain multiple levels of amplification.
An amplifier’s last stage might only provide half a watt of power in a small amplifier, such as an amplifier in a speaker phone.
The final stage of a home stereo amplifier can generate hundreds of watts.
Thousands of watts of power can be generated by the amplifiers used in outdoor music concerts.
Distortion is the enemy of a decent amplifier, which is why they make them.
Even if the final signal driving the speakers has been increased numerous times, it should be as near to the original input signal as possible.
Any sort of signal can be amplified using this strategy, not only audio ones.
Radio and television signals, for example, can be amplified in the same way that electrical currents can be used to carry them.
In terms of attracting attention, audio amplifiers seem to be the most popular.
Variations in design that impact, for example, power rating, impedance, and quality, captivate audiophiles.