Coil Physical Properties Calculator

This Coil calculator calculates the resistance, total length of wire required, and number of windings for a coil, as well as the wire diameter and bobbin length. For resistance and voltage calculations, the Coil Inductance calculator assumes copper wire. The Coil calculator online calculates resistance and voltage on the assumption that the wire is copper. Wires are twisted around a bobbin or core form in both inductors and electromagnets. It is vital to estimate the cross sectional area and coil resistance while designing and building the coil.

Coil Parameters Calculator
Wire Diameter mm
Number Turns turns
Bobbin Length mm
Bobbin Diameter mm
Rated DC Current (Optional) A
Results
Turns/Winding Turns
Number of Windings Windings
Coil Diameter
mm
in
Cross sectional Area
mm2
in2
Total Length of Wire in Coil m
Resistance/meter ohms/m
Resistance ohms
Voltage at Rated Current V
Power at Rated Current W
Introduction

In this lesson, I will explain you the structure and working principle of the coils which is one of the basic circuit devices of electricity and electronics.  Coil is also called as inductor.  Unit of the coil is Henry and  is denoted by the letter L. In daily life, they are used as toroid, resistance and surface mounting types.   Coil is the circuit device that is formed by winding a conductive wire over and over.  Coils are composed of winding and core. In coil windings, varnished insulated copper wire is used. This feature allows the coil to store electrical energy as a magnetic field. It is mostly made of a  ferromagnetic core such as , iron which has very good magnetic permeability to increase the strength of the magnetic field in inductors.

What is a Coil? How Does a Coil Work? Where is Coil Using? (Coil Tutorial)

Introduction of Coil Physical Properties Calculator

This Coil Calculator is a professional and easy-to-use electrical tool for electrical engineers and designers. This online Coil inductance calculator can help you to calculate physical properties, including turns/winding, number of windings, coil diameter, resistance and voltage & power at rated current through entering the values of wire diameter, number turns, Bobbin Length, Bobbin Diameter and Rated DC Current.

What is an Electric Coil?

An electric coil, also known as an electromagnetic coil, is an electrical conductor made up of a number of conductive wires wrapped around a cylindrical, toroidal, or disk-shaped ferromagnetic core. Electric coils are one of the most basic types of electronic components, providing inductance in an electrical circuit, which is an electrical property that resists current flow.

The gauge of the wires, coil diameter, wire lengths, number of loops, and kind of core material, which might be air, iron, steel, ceramic material, or iron-based formless tape, all affect the price of electrical coils. The permeability of the material, which is the capacity of the core to produce a magnetic field, determines the materials used for the core of an electric coil.

Electric motors, generators, inductors, and electromagnets all use electric coils. They act as a conductor of electricity, allowing electrical current to flow effectively to electric motors. They are a constant and dependable induction approach.

Types of Electrical Coils

The type of electrical coil to employ is decided by the project's requirements, which include whether a DC or AC electric motor is required. Electric current interacts with a magnetic field in all electric coils, regardless of kind. Motors, generators, transformers, magnetics, and sensors all require different sorts of coils. Coils are used in a variety of applications in electronics, electricity, and magnetism. A quick summary of the many types of coils may be found below.

Bobbin Wound Coils

A bobbin is a coil of magnetic wire that has been coiled around a plastic core. Plastic cores are available in a variety of diameters, and bobbin wrapped coils can be impregnated, molded, or taped to satisfy the needs of medical devices, sensors, relays, and automobiles.

Choke Coils

Choke coils have a high inductance and low resistance. They're suitable for both AC and DC currents. Choke coils are designed to block AC while allowing DC to pass through. Choke coil resistance rises as the frequency of the current rises.

Self-Supported Coils

When there isn't enough area for a bobbin or core, this type of coil is employed. They have better magnetic capabilities since they may be put closer to the metal in the circuit. Clutches, magnetic locks, and audio circuitry all utilise them.

Encapsulated Coils

Encapsulated coils, also known as molded coils, are encased in a durable temperature-resistant thermoplastic that protects them against moisture, corrosive chemicals, vibration, explosions, and hostile working conditions. Encapsulated coils have more insulation and dielectric qualities due to their design.

Tape Wrapped Coils

Taped wrapped coils are intended for use in mild to moderately harsh conditions that are free of chemicals and solvents. A sealing tape is used to protect the coil from the elements, dirt, and vibration. Tape wrapped coils are a cost-effective option since they are less expensive than other varieties.

Toroidal Coils

Inductors and transformers both employ toroidal coils. Wrapping a wire around a circular core with an open center creates the coil. A toroidal coil's form provides for magnetic field confinement, minimizing the amount of field leakage outside the coil. They're employed in a wide range of sectors, including transportation, audio, and power supply.

Tesla Coil

A Tesla coil is a resonant transformer powered by a radio frequency oscillator that converts high voltages to low voltages. It's made up of two open electric circuits linked by a spark gap. Tesla coils should be composed of copper wire for the optimum performance.

Transformer Coils

A transformer coil's function is to convert voltage from one electrical circuit to another. Voltage may be reduced or increased using transformers. It's a passive device that steps voltage levels up or down between different circuits using electromagnetic induction.

Voice Coils

A bobbin, wire, collar, adhesives, and lead out wire make up a voice coil. The diameter of the voice coil gap determines the bobbin size. Electrical impulses are converted into linear magnetic energy by a voice coil. A voice coil was first used to move the cone of a speaker. Its use has broadened to include the movement of enormous masses at modest speeds. The Lorentz force is the force that exists between the magnetic field of the voice coil and the electric current flowing through it.

High Voltage Coils

In situations where the voltage is higher than what is deemed safe, high voltage coils are employed. The use of the term "high voltage" implies that the current is potentially hazardous owing to the possibility of sparks or electric shock. For AC circuits, the classification is 1000 volts, while for DC circuits, the classification is 1500 volts. Ignition and Tesla coils are the two forms of high voltage coils.

Ignition Coils

To fire a spark plug, ignition coils convert lower voltage electricity to higher voltage. They feature main and secondary coil windings, similar to an electric transformer. The automotive sector is the most prevalent and well-known application of ignition coils.

Impregnated Coils

The empty space in the winding of an impregnated coil has been impregnated with resin or another substance to minimize conductor motion. The substance used in the procedure is intended to seal the holes in the coil's construction. They have a low viscosity, a long service life, strong dielectric strength, and can withstand severe temperatures.

Solenoid Coils

A conductive core with a hollow center and wire wrapped around the hollow center makes up a solenoid coil. As current runs through the solenoid coil, it produces a magnetic field, which generates magnetic potential, which is then converted to magnetic force for mechanical motion. A metal core can sometimes cause a hydraulic valve to open or close.

Coil Formula

a = PI x r x r
cd = (2 x n x d) + bd
L = (2 x PI x r x n) / 1000
n = Turns/ T
P = V x I
r = (n x d + bd) / 2
R = rpm x L
rpm = .0333 *((0.812/2)*(0.812/2))/((d/2)*(d/2))
T = bl / d
V = R x I

Where,
a = Cross sectional area,
bd = Diameter of Bobbin,
bl = Length of Bobbin,
cd = Outer diameter of coil,
d = Wire Diameter,
I = Current,
L = Total Length,
n = Number of windings,
P = Power at Rated Current,
r = radius of middle of coil,
R = Resistance,
rpm = Resistance/meter,
T = Turns per winding,
V = Voltage at Rated Current,

How to Calculate Coil Physical Properties

How to Calculate Number of Turns in a Coil

How to Calculate the Inductance of a Coil?

How to Calculate Coil Windings?

Inductors are made from electrical wrapping wire. An inductor is a coil of wire wound around an iron core. The inductance value is determined by the number of turns on the coil wire. Transformers and electric motors are two examples of electrical devices that employ inductors. In actuality, the transformer ratio is the ratio of the main and secondary windings, with windings referring to wire coils. As a result, calculating the value of the inductance associated with an electrical winding wire is similar to calculating the value of the inductance associated with the winding.

In meters, get the radius of the wire coil or winding. Measure the winding using a micrometer from the center of the wire coil to the outside part of the coil, or refer to the manufacturer's specifications. This value will be referred to as "r." Use the formula A = pi * r2 to get the area of the winding, where pi is 3.1415.

How to Calculate the number of Coils?

The number of times a wire is wrapped around the armature is measured in turns. Simply put, a single wind will give you more punch, while a higher wind will offer you a smoother uptake and a little greater maximum speed. Run time is affected by both winds and turns; a larger number of turns and a single breeze will give you more run time. The total number of turns and turns per volts are calculated using the number of turns of a coil formula.

Both the overall number of turns and the turns per volts are calculated using the Number of Turns of a Coil formula. The formula for turns per volts is (1/(4.44 * F * M * A)), where F is the operating frequency, M is the magnetic flux, and A is the core area. The formula for total number of spins is (Turns per volts * voltage).

Wire Gauge Chart

Wire Gauge Chart
AwgDia InchDia mmResistance Ohms/M CopperAwgDia InchDia mmResistance Ohms/M Copper
4/0=00000.4611.70.000161220.02530.6440.053
3/0=0000.4110.40.000203230.02260.5730.0668
2/0=000.3659.260.000256240.02010.5110.0842
1/0=00.3258.250.000323250.01790.4550.106
10.2897.350.000407260.01590.4050.134
20.2586.540.000513270.01420.3610.169
30.2295.830.000647280.01260.3210.213
40.2045.190.000815290.01130.2860.268
50.1824.620.00103300.010.2550.339
60.1624.110.0013310.008930.2270.427
70.1443.660.00163320.007950.2020.538
80.1283.260.00206330.007080.180.679
90.1142.910.0026340.006310.160.856
100.1022.590.00328350.005620.1431.08
110.09072.30.00413360.0050.1271.36
120.08082.050.00521370.004450.1131.72
130.0721.830.00657380.003970.1012.16
140.06411.630.00829390.003530.08972.73
150.05711.450.0104400.003140.07993.44
160.05081.290.0132410.00280.071124.34
170.04531.150.0166420.002490.06335.47
180.04031.020.021430.002220.05646.9
190.03590.9120.0264440.001980.05028.7
200.0320.8120.0333450.001760.044710.98
210.02850.7230.042



Frequently Asked Questions

How does wire thickness impact coil performance?

Thinner wires increase resistance per meter (e.g., 0.0333 Ω/m for 0.812mm diameter). Thicker wires allow fewer turns per layer but reduce resistance. The calculator dynamically adjusts results based on input wire diameter 

What is the purpose of the "Rated DC Current" field?

This optional input calculates voltage (V = I * R) and power (P = I * I * R) at the specified current. It helps designers evaluate thermal limits and ensure safe operation without overheating  

How is total wire length calculated for a coil?

Total length depends on the average coil diameter and number of turns. The formula uses: Length = π * (Bobbin Diameter + Wire Diameter) * Number of Turns, with adjustments for winding density  

Why does the calculator exclude core material properties?

It focuses on air-core coils and single-layer windings. For cores like iron or ferrite, permeability and hysteresis losses require advanced tools beyond this calculator's scope
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