Types of Amplifiers and Comparators

What are Amplifiers?

amplifierAmplifiers are devices that increase the power of an input signal. They're most typically found in audio equipment, though they're used in myriad other applications, as well. In order to increase the power of an input signal, the amplifier draws power from a power supply and produces another signal that is larger in terms of amplitude but that still stays true to the characteristics of the original audio signal.

Amplifiers exhibit different qualities and, in some cases, those qualities can mean that certain types of amplifiers are chosen based on subjective criteria. For instance, amplifiers used for musical instruments are typically either transistor designs or tube designs. While transistor designs are more compact and more efficient, some musicians prefer tube amplifiers because they generate what most regard to be a warmer tone than transistor amplifiers.

amplifierAmplifiers are such common examples of electrical components that there are designs that are found in just about every consumer device and designs that are highly specialized in their applications. Many of them are available in the form of integrated circuits, which contain all of the circuitry for an amplifier in one durable and easily installed component.

How do Amplifiers work?

Most amplifiers are powered by transistors. There are also designs that utilize vacuum tubes. The way these amplifiers work is similar, in either case.

In transistor amplifiers, a semiconductor material is utilized to obtain the amplifying effect. The amplifier has an input for a small electrical current produced by a device such as a microphone, an electric guitar pickup or another, similar, device and an input for the much larger electrical charge produced by the power supply. Within the semiconductor, the electrons are more or less fixed in their positions when there is no current applied to the amplifier, but current frees them up to move across the various layers of semiconductor material within the device. .

The end result is that the low electrical current produced by the microphone or other input device is increased in its power by the additional current produced by the power source. The semiconductor materials – or the materials utilized in the vacuum tube – allow this signal to be increased while keeping it faithful – which is where the term 'high fidelity' comes from – to the original signal. Good amplifiers are able to increase the power of the signal without introducing distortion into it, which is a basic measure of their overall quality.

Some amplifiers have specialty features, such as the ability to produce a variable level of gain dependent upon a control voltage. Other amplifiers are designed specifically to work with radio frequencies and in other applications, where they provide control functions or simply amplify signal enough so that it can, for example, drive an antenna used to transmit a radio signal for a radio station or for another purpose.

Amplifiers are found as widely in industrial applications as they are in consumer applications. For example, RF amplifiers are used in RF control devices, which include everything from the most sophisticated control devices utilized in industrial settings to control machinery and other equipment as well as the very simple RF controllers that are utilized to change the channels on a television, turn a stereo on and off and to provide additional control over devices without the user having to interact with that device physically.

What are Amplifiers used for?

In the vast majority of cases, you'll find amplifiers utilized to drive speakers. There are other applications, however, which take advantage of the fact that amplifiers can increase the power of a signal.

Some amplifiers are used in radio devices to amplify radio signal. These are referred to as RF power amplifiers. Other amplifiers are utilized in mechanical applications, such as those used to increase the signal put out to servomotors. Amplifiers are also used in video applications, oscilloscopes and many other capacities. Add to their already considerable potential for usage the fact that amplifiers can be variable, and it's easy to see why they are so heavily employed in so many different electronic designs.

What are Comparators?

A comparator is an electronic component that functions in a similar fashion to an amplifier. The essential difference is that, instead of actually amplifying a signal, a comparator merely has to inputs and matches its output to the level of the most powerful input. These devices are oftentimes employed in analog-to-digital converters; devices that are quite frequently found in use in the music industry taking analog recordings and converting them to a more modern digital form.

How do Comparators function?

Comparators can produce positive output or negative output, depending upon which input is higher. If the positive input is higher than the inverting input, it will produce positive output. If the inverting input is higher than the positive input, it will produce negative output.

What are Comparators used for?

Operational amplifiers are the most common incarnations of comparators. They are most frequently used in converters that take analog signals and convert them to digital signals.

Comparators are also utilized in devices called null detectors. These are detectors that are designed to indicate when a specific value is equal to zero. Other applications include lever shifters, relaxation oscillators, zero crossing detectors and more.

What types of Amplifiers and Comparators exist?

Amplifiers and ComparatorsThere are many different types of amplifiers and comparators, some of which are detailed below. Many of these devices are very specific to a given function.

What are Analogue Multipliers & Dividers?

Analogue multipliers and dividers can produce output current that is calculated as a proportion to the input voltages it receives. There can be two or more input voltages fed into these devices. These devices can perform sophisticated calculations, such as square routing, squaring and more. These devices are commonly found in the control circuits used in industrial applications and in radar circuitry.

What are Audio Amplifier Filter Boards ?

Audio amplifier filter boards provide various processing capabilities that allow the signal to be more faithfully reproduce. For example, a low pass filter is designed so that switching noise is attenuated and so that the output signal is reproduced as faithfully as possible to the input signal.

What are Audio Amplifier ICs?

Audio amplifier ICs are integrated circuits that contain within them a complete amplifier set up. They make it possible to reduce very compact devices with sophisticated amplification capabilities.

What are Audio Amplifier Power Supply Units?

Audio amplifier power supply units come in three basic types:

• Unregulated power supplies

• Linear regulated power supplies

• Switch mode power supplies

The power supply provides the means by which the amplifier actually increases the output power of an input signal. Each of these different technologies has its own advantages and disadvantages, which are considered when designing an amplifier circuit.

What are Audio Amplifier Printed Circuit Boards?

Audio amplifier printed circuit boards contain an amplifier circuit on the familiar PCB design. These are very convenient, in that the builder doesn't have to wire the various components together and because of their compact nature.

What are Audio Volume Controllers?

Audio volume controllers come in various designs, but all are designed to increase or decrease the power given to the speaker that receives the output from an amplifier. Some of these are simple potentiometers that are adjusted by manually rotating a dial and others are digital devices that increase or decrease volume at specific increments by pressing buttons.

What are Channel Protectors?

Channel protectors are devices that are designed to protect sensitive components from variations in voltage. These devices can be designed to use with unipolar and bipolar power supplies and they have numerous different applications.

What are Compandors?

CompandorCompandors get their name from combining the words compressing and expanding. They are utilized on circuits that have limited dynamic ranges, allowing an input signal to be compressed or expanded as needed, to compensate for that limited dynamic range. These components are commonly used in telephony.

What are Comparators?

Comparators actually compare the input power of the signals that they are receiving and output a signal based on which of them is higher in power. These are very common components and have myriad different applications.

What are Current Loop Transmitters?

Current loop transmitters are utilized to provide control functions over devices. They are commonly utilized in industrial applications.

What are Current Sensing Amplifiers?

current sensing amplifier is a specialized type of amplifier whose output voltage is proportional to the amount of current flowing through a rail. These come in various architectures for use in a variety of different applications.

What are Differential Amplifiers?

Differential amplifiers generate their output signal based on different criteria than standard amplifiers. In a differential amplifier, the output signal is dependent upon the difference between the two input signals, rather than on the value of any one particular signal.

What are Differential Line Drivers?

Differential line drivers are utilized in digital signaling and in balanced audio circuitry. These components transmit a signal based on what they receive from two input signals, which are referred to as the differential pair. These types of drivers are typically used in applications where electromagnetic noise is an issue.

What are Differential Line Receivers?

Differential line receivers work on the same twisted-pair wiring as do differential line drivers. These are also utilized in applications where electromagnetic noise is known to be an issue.

What are Instrumentational Amplifiers?

Instrumentational amplifiers are utilized in various types of testing equipment. They include buffer amplifiers, and one of their distinguishing features is typically the presence of 3 op-amps in their design.

What are Isolation Amplifiers?

Isolation amplifiers function as safety devices. They provide insulation for certain types of circuitry against variable voltages, which may cause harm. The also insulate against electromagnetic noise.

What are Logarithmic Amplifiers?

Logarithmic amplifiers are also referred to as log amplifiers. These devices produce an output voltage that has a logarithmic relationship to the input voltage. They can only function on positive input voltage and are sometimes combined with a filter and a rectifier to accommodate this.

What are Operational Amplifiers?

operational amplifier are referred to as op-amps in common usage. An operational amplifier is a high gain amplifier that typically has a single output. These have a long history of usage, being used in analog computers but still being used in a great many different applications today.

What are Parametric Measurement Units?

Parametric measurement units are oftentimes incorporated into industrial computers and are utilized for test applications.

What are Programmable Gain Amplifiers?

Programmable gain amplifiers are typically used on sensing equipment, signaling equipment and devices that provide control over electric motors. They are electronic amplifiers that have a variable gain, which is controlled by either analog or digital signals.

What are RF Amplifier Modules?

RF amplifier modules are units that are designed to provide amplification to RF signals but that combine all of the necessary circuitry into a modular component. These are used in many different applications, owing to their convenience and durability.

What are RF Amplifiers?

RF amplifiers are designed to take low-power radio signals and to increase their power for various applications. These are commonly found in use increasing the power of weak radio station signals so that they are strong enough to drive an antenna. They are also utilized in radar equipment.

What are RF Controllers?

RF controllers utilize radio waves to allow for control over electronic devices or other devices. These are used in both consumer and industrial capacities and have a nearly endless range of applications.

What are Transimpedance Amplifiers?

Transimpedance amplifiers are devices that can take an electrical current and converted into a voltage. The most common application for these particular devices is in photodetector technology.

What are Video Amplifier ICs?

Video amplifier ICs are devices that contain all the necessary components for a video amplifier in one integrated circuit. These are inexpensive and very durable solutions for video amplification needs and are in widespread use.

What are Voltage Controlled Amplifiers?

voltage controlled amplifier is a device that has the capacity to produce variable gain. The gain is controlled by a control voltage. These devices have many different applications, including being used for amplitude modulation, audio level compression and other purposes.