Electric Guitar Working Principle

Electric Guitar

In the world of musical instruments, the electric guitar is one of the coolest and widely used instruments. Before the arrival of electric guitars, acoustic guitars were more prevalent in the music industry. The advent of the electric guitar was observed in 1936 when a guitarist named Charlie Christian used the acoustic guitar by attaching magnetic pickups with the body of the guitar. This remarks the birth of electric guitars. The electric guitar is a passive device as it does not need any source for the power supply; instead, the power is generated with the help of magnetic pickups attached to the electric guitar through the phenomena called, electromagnetic induction. Its unique ability is that one can play various kinds of styles and genres by using just a single instrument, i.e., electric guitar. In this article, we’ll learn the various concepts of electric guitar, specifically the working principle behind the functioning of electric guitar.

Components of Electric Guitar

To understand the electric guitar, let’s first understand the various components that are used for its construction.

1. Body

The body of the guitar is referred to as the big curvy part at the lower side of the guitar, which rests against the body of the player. The electric guitar can have a solid, hollow, or semi-hollow body. The body is generally made of wood, but some modern guitars are also built of other materials like synthetic material or carbon fibre.

Body of Electric Guitar

2. Neck

The neck is another major part of the guitar after the body. It is a thin long component over the body on which the strings are attached. The strings of the guitars are mounted throughout the neck. The neck is also used to comfortably hold the guitar while playing it.

Neck of Electric Guitar

3. Fingerboard

The fingerboard is the neck area underneath the strings of the guitar. This area is basically the scale of the electric guitar, which has markings that guide the guitarist to depress the strings at certain points to generate the required notes. Maple wood and rosewood are the commonly used materials for the construction of the fingerboard.

Fingerboard of Electric Guitar

4. Frets

The frets are the thin metal strips (fret bars), which are extended over the full length of the neck of the electric guitar. It helps the player to find the exact note spots easily. In the standard western system, each fret means one semitone, and one octave consists of twelve semitones. The player can adjust the height of the fret according to his/her taste of the music. The very high and widely attached frets are suitable for soloists, and the low and narrow frets are best for the vintage type. The medium frets are used by versatile musicians for playing both the solos as well as vintage music.

Frets of Electric Guitar

5. Truss-rod

The truss rod is the metallic bar (usually made of steel), which is fitted inside the neck of the guitar. The function of the truss rod is to maintain the curvature of the neck by preventing the tensions due to the strings.

Truss-rod of Electric Guitar

6. Headstock

It is attached at the end of the guitar’s neck. All the strings of the guitar are attached to the headstock.

Headstock of Electric Guitar

7. Tuning Pegs/ Turners/ Machine Heads

These refer to the knobs/bits that help to tune the guitar. The strings are wounded on the tuning peg, and if we tighten or loosen the strings, the pitch of the electric guitar can be changed.

Tuning Pegs of Electric Guitar

8. Nut

The nut is a small piece of wood or plastic at the point where the neck and the headstock of the guitar joins. It holds the strings of the guitar at an accurate distance from the fingerboard.

Nut of Electric Guitar

9. Strap Buttons

As suggested from the name itself, these are the two metal buttons that are mounted over the body of the guitar, on each side, to attach the strap.

Strap Buttons of Electric Guitar

10. Bridge

The bridge supports the strings of the guitar, and it is used to adjust the distance between the fingerboard and the strings by adjusting the height of the bridge. It also acts as a component that helps to transfer the vibrations of the strings towards the magnetic pickups.

Bridge of Electric Guitar

11. Saddles

Saddles are attached at the opposite end of the nut. They are used to adjust the strings individually as per the requirement.

Saddle of Electric Guitar

12. Tailpiece

The tailpiece is present behind the bridge. It secures the strings at their place and prevents them from tangling.

Tailpiece of Electric Guitar

13. Pickups

Pickups are the most important component of electric guitars. It captures the string’s vibrations and transforms them into electric signals, which eventually generates the sound from the guitar’s amplifier. The magnetic pickups consist of magnets, copper wire coil, and poles. Typically used magnets in electric guitars are ceramic, Alnico II, and Alnico V.

  • The Alnico II is a slightly weaker magnet and used for slight warm tones or audios.
  • The Alnico V is a strong magnet having low inductance, and it is used for bright tones.
  • Ceramic is the strongest magnet than both the Alnico II and Alnico V. These magnets maintain the clarity of the sound even in the distortion, hence it is suitable for the heavily distorted styles.

The tone generated by the electric guitars is largely dependent upon the types of pickup used and its position in the electric guitar.

Different Types of Pickups

There are three main types of electric guitar’s pickups, which are single-coil pickup, humbucker pickup, and P90 pickup. Let’s briefly understand them.

1. Single Coil Pickup

As suggested from the name, the single-coil pickups consists of a single magnet. The Fender Telecaster was the first guitar that consisted the single-coil pickups. These pickups are easy to identify as they are usually thin and long compared to the other two types of pickups. Single coil pickup is widely used by musicians as they provide crisp and bright sound; however, they are not preferred for the high distortions as they are susceptible to undesirable noise signals.

Single Coil Pickups

2. Humbucking Pickups or Humbucker

These pickups are called the humbuckers as they are designed to ‘buck’ the ‘hum,’ i.e., they cancel out the noise signal called 60-cycle hum. The humbucker consists of two magnets, where one magnet is used as a pickup and the other is used to cancel the hum. These pickups are preferred for the high distortions levels as they have high output and dark voice, which is why they are usually used for playing jazz.

Humbucking Pickups

3. P90 Pickup

The efficiency of the P90 pickups is somewhat between the humbucking pickups and the single-coil pickups. The output of the p90 pickups is higher than the single-coil pickups but lesser than the humbucking pickups. They can be easily identified as they are quite larger than the single-coil pickup and the humbucking pickups, and on their front face, they consist of six outward bulged metallic dots.

P90 Pickup

Role of Pickup Position on Tone

The position of the pickup is closely related to the tone produced by the electric guitar. The pickups only detect the nearby vibrations, and it does not sense the far-away harmonics. Let’s discuss the effect on the tone of the electric guitar according to the different positions of the pickups.

1. Pickup Near the Bridge/Bridge Pickup

If the pickup is placed near the bridge, the magnitude of the fundamental string vibration will not be much strong, but the higher frequency vibrations will have a larger magnitude. As seen in the image below, the magnitude of the fundamental frequency is smaller than the third harmonic. As the higher harmonics have a large magnitude so they give a brighter tone. The pickups placed near the bridge consists of a high number of turns in the copper coil, which makes the pickup more sensitive to the slight changes in the magnetic field. The tone of the pickup near the bridge provides high treble due to the more number of turns.

Pickup Near the Bridge

2. Pickup near the Neck/Neck Pickup

When the pickup is placed near the neck of the guitar, it becomes more sensitive to the fundamental frequencies as compared to the higher harmonics. Due to this reason, it generates a clean and mellow tone that synchronizes well with the cords. In the popular Gibson’s electric guitars such as Les Paul, the neck position of the pickup is termed as the ‘Rhythm’ position.

Pickup Near the Neck


3. Middle Pickup

Some of the electric guitars are also provided with the middle pickups. The middle pickup’s tone is in between the neck pickup and the bridge pickup, i.e., it is more clear and bright than the neck bridge but less clear and bright than the bridge pickups.

14. Pickup Selector Switch

The pickups are the most important component of electric guitars that differentiate them from acoustic guitars. Different pickups are placed at different positions of the strings, which provides different tones. Different type of pickups such as single-coil, twin coiled, and humbuckers also provides different tones. The selector switch is used to select the required pickup.

Pickup Selector Switch


15. Volume and Tone Controller

Volume and tone controllers are the knobs present near the pickups. The volume control knob controls the signal level generated from the pickup, and the tone control adjusts the brightness of the signal.

Volume and Tone Controller of Electric Guitar

16. Jack Socket

It is used to plug in the lead of the electric guitar.

Jack Socket of Electric Guitar

Working Principle of Electric Guitar

The working principle of the electric guitar is based on the laws of electromagnetic induction. According to the electromagnetic law of induction, if a magnet is moved in and out of the copper wire coil, it will result in the induced electric current in the copper coil due to the change in the magnetic flux. In the same manner, if the magnet is kept stationary and the copper coil is moved back and forth within the magnetic field of the magnet, the current will induce in the coil. Hence, by moving the copper coil or by varying the magnetic field, the electric current can be induced in the coil. This phenomenon is termed electromagnetic induction, and it is the basic working principle of the electric guitar. As discussed above, the electric guitar consists of magnetic pickups, which are small magnets with very fine copper wire coils of around 4000 to 7000 turns. The magnetic pickups generate the magnetic field around them. Now, as discussed, a varying magnetic field is required for the induction of the electric current in the coil, and in the electric guitar, this is done with the help of the strings. The strings of the electric guitar are magnetized by magnetic pickups. When the guitarist strung the metal strings, the air around the metal strings gets disturbed from the equilibrium and the vibration motion generates around the magnetic field of the magnetic pickups, which result in the change in the magnetic flux. Now eventually, the law of electromagnetism comes into play, and an electric charge produces in the wire coil that surrounds the magnet. Generally, the arrangement of the magnetic pickups contains six small magnets. The distance of the magnets from the metal strings can be adjusted with the help of the knob. The closer the magnets will be with the metal strings, the stronger will be the electric signal generated by the guitar. Each string attached to the guitar vibrates at a specific rate. The total amount of electric charge generated by the vibrating motion in the coils is transmitted to an electric circuit. The electric circuit consists of the resistor, capacitor, this helps in controlling the amplitude and tone of the electric signal. This signal is of around a few hundred millivolts (mV), which is further transferred to the amplifier that is attached to the magnetic pickups to increase the amplitude of the signal and make it loud. The overall magnitude of the signal depends upon the string gauge, the number of coils, and the way the string is plucked.

Working Principle of Electric Guitar

Working Principle of Electric Guitar

Types of Electric Guitar

Electric guitars are available in different types, but they are broadly categorized into two types, i.e., Archtop electric guitar and solid-body electric guitar.

Archtop Electric Guitar

The Archtop electric guitar consists of a semi-hollow sound chamber and a solid wooden block that runs through its middle. This semi-hollow sound chamber adds some characteristics of acoustic guitars into it. The magnetic pickups are embedded over the block that detects the vibrations of the string and transfer them to the amplifier. These guitars are provided with knobs to adjust the tone and volume, and selector switches to select the required pickup. The archtop guitars are primarily used for playing mellow music that has the elements of both electric and acoustic guitar music. They are used for playing a wide variety of music styles, but they are best known for playing blues and jazz. The popular archtop guitars include the Gibson ES-335, Gibson ES-150, Gretsch G5420, and the Epiphone Casino.

Archtop Electric Guitar

Solid-body Electric Guitar

Unlike the Archtop electric guitars, Solid-body guitars do not consist of any hollow sound chamber; rather, they are fully solid from inside. Other features like magnetic pickups, volume control and tone controller knobs, and the amplifier are attached to the Solid-body electric guitar, similarly to the Archtop electric guitar. The solid-body electric guitars generate minimal sound, which is why the amplifier is necessary with an archtop amplifier. They are primarily used to play pop and country music.

Solid-body Electric Guitar

Acoustic Guitar vs Electric Guitar

Acoustic Guitar vs Electric Guitar

The body of the Acoustic guitar is hollow from the inside and only consists of air, and when the strings of the acoustic guitar are strung, the large wooden body of the guitar vibrates, which makes the inside air vibrate. The vibrations of the wooden body and the air amplify the sound that we hear from the guitar. The Acoustic guitar consists of large holes under the strings, in the middle of the guitar’s body through which the amplified sound escapes and we hear the sound. The body of the electric guitar is usually solid and sometimes semi-solid. Electric guitars are usually constructed from wood, and unlike acoustic guitars, the functioning of the electric guitar does not depend upon the type of material used for its construction. The pioneer of electric guitar George Beauchamp had said that

The body may be varied considerably in size, shape, and construction, and may be constructed of various materials without departing from the spirit of the invention.”

The functioning of the electric guitar does not depend upon the type of materials used for its construction because the working of the electric guitar is based on the tension of the strings. The electric guitar must need an amplifier to generate a sound of suitable amplitude while the sound produced by acoustic guitars is based on its hollow design and the soundhole, hence it does not require any external device to amplify sound. The strings used in electric guitars are made of steel, while the strings of acoustic guitars could be either steel or nylon. The acoustic guitars are used to play classic folk and country music, while the electric guitars are used to produce rock music. The electric guitars are provided with various switches, buttons, and knobs, while acoustic guitars do not have any of those. The electric guitars are comparatively easier to play than acoustic guitars as the strings of the acoustic guitars are quite hard to pluck.

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