Contents

- 1 How do you increase inductance?
- 2 How do you make an inductor coil for a speaker?
- 3 How do you create a coil for specific inductance?
- 4 How do you make a RF coil?
- 5 Why does inductor block AC and allows DC?
- 6 What is inductor formula?
- 7 What does an inductor do in a crossover?
- 8 How do you calculate the number of turns in a coil?
- 9 How do you read an inductor value?
- 10 How do you calculate inductors?
- 11 How do you wind a coil?
- 12 How do RF coils work?
- 13 How is toroid inductance calculated?

## How do you increase inductance?

As well as **increasing** the number of coil turns, we can also **increase inductance** by **increasing** the coils diameter or making the core longer. In both cases more wire is required to construct the coil and therefore, more lines of force exists to produce the required back emf.

## How do you make an inductor coil for a speaker?

- There are a wide range of materials and shapes used in the manufacture of
**Loudspeaker Inductors**. - (1) You need an
**Inductance**meter. - (2) For small value
**inductors**, say less than 0.4mH in value use an air cored bobbin, size 17mm by 40mm diameter and thickish wire (0.8 to 1.0)mm wire should be fine.

## How do you create a coil for specific inductance?

The length of the **coil** used in the **inductor** should be equal to or 0.4 times the diameter of the **coil**. As shown in the equation, **inductance** of the air-core **inductor** varies as the square of the number of turns. Thus the value ‘l’ is multiplied four times if the value of ‘n’ is doubled.

## How do you make a RF coil?

Depending upon fixed or variable **RF coil** design suitable core need to be choosen and any conductor such as insulated thin copper wires are wrapped around the core. Material of the core is selected based on the operating frequency. For variable **inductor** shielded slug tuned **inductor** form is used.

## Why does inductor block AC and allows DC?

Since **inductor** behaves like a resistor, **DC** flows through an **inductor**. The **AC** flowing through L produces timevarying magnetic field which in turn induces self- induced emf (back emf). This back emf, according to Lenz’s law, opposes any change in the current.

## What is inductor formula?

Now we have an **inductor** with its i- v **equation**: v = L d i d t v = text L,dfrac{di}{dt} v=Ldtdiv, equals, start text, L, end text, start fraction, d, i, divided by, d, t, end fraction. This tells us the voltage across the **inductor** is proportional to the change of current through the **inductor**.

## What does an inductor do in a crossover?

A **crossover inductor** acts in the reverse manner — it is only a good conductor when the frequency is below a certain level. When the electrical audio signal travels through the speaker wire to the speaker, it passes through the **crossover** units for each driver.

## How do you calculate the number of turns in a coil?

If you know the **number of turns** in the secondary **coil** and primary and secondary voltages. You can find out the **number of turns** in the primary using this **formula**: Np/Ns = Vp/Vs. where Ae is the area of the core – this is fine for Si-steel & copper xfmrs – unless you know a lot about the steel, keep the Bpk to 1.2T.

## How do you read an inductor value?

First two digits indicate the **value**. Third digit is the power to be applied for the first two, this means it is the multiplier and power of 10. For example, 101 is expressed as 10*101 micro Henry (µH). Suffix or fourth letter or alphabet represents the tolerance **value** of the **inductor**.

## How do you calculate inductors?

The sum of the individual voltage drops across each **inductor** can be found using Kirchoff’s Voltage Law (KVL) where, V_{T} = V_{1} + V_{2} + V_{3} and we know from the previous tutorials on **inductance** that the self-induced emf across an **inductor** is given as: V = L di/dt.

## How do you wind a coil?

To start winding a **coil**, put the spacing block or tube inside the form and insert one end of the **coil** wire and spacing line in the side-by-side holes at one end of the form. **Wind** the **coil** by rotating the form on its axis.

## How do RF coils work?

**Radiofrequency coils** (**RF coils**) are the receivers, and sometimes also the transmitters, of **radiofrequency** (**RF**) signals in equipment used in magnetic resonance imaging (MRI). The receiver **coil** picks up the oscillations at **RF** frequencies produced by precession of the magnetic moment of nuclei inside the subject.

## How is toroid inductance calculated?

Approximate **Inductance** of a **Toroid**

This can be used with the magnetic field expression above to obtain an expression for the **inductance**. **Toroidal** radius r = cm with N = turns, Coil radius = cm gives area A = cm^{2}. L = Henry = mH.