# How to find value of inductance in LR series circuit?

• mathman44
In summary, the speaker is asking for help calculating the inductance "L" based on measurements of voltage drop across a resistor at different frequencies in an LR series circuit. They are also inquiring about the reactance XL as a function of frequency and plan to use geometry to solve for L.

#### mathman44

Hi. This is a question from my lab. I have a series of measurements of the voltage drop across a resistor for various frequencies with a constant voltage source in an LR series circuit. From these measurements I am supposed to calculate the value of the inductance "L". How can I do this?

For homework help you have to show some work to get some help.

What is the reactance, XL as a function of frequency?

XL = $$2*pi*f*L$$

OK... are you going to solve for L using geometry or the equations for complex impedence?

Geometry. Got it, thanks.

Good deal.

## 1. What is the formula for calculating inductance in an LR series circuit?

The formula for calculating inductance in an LR series circuit is L = XL / ω, where L is the inductance in henries, XL is the inductive reactance in ohms, and ω is the angular frequency in radians per second.

## 2. How do I measure the inductance in an LR series circuit?

To measure the inductance in an LR series circuit, you can use an inductance meter or an oscilloscope. Alternatively, you can use a multimeter in conjunction with a known value of resistance and frequency to calculate the inductance using the formula L = XL / ω.

## 3. What factors affect the value of inductance in an LR series circuit?

The value of inductance in an LR series circuit is primarily affected by the number of turns in the inductor coil, the material used for the core of the inductor, and the physical dimensions of the inductor. The frequency of the current passing through the circuit can also affect the inductance.

## 4. Can the inductance in an LR series circuit be changed?

Yes, the inductance in an LR series circuit can be changed by altering the physical characteristics of the inductor, such as the number of turns or the material used for the core. Additionally, the inductance can also be changed by adjusting the frequency of the current passing through the circuit.

## 5. Why is it important to know the value of inductance in an LR series circuit?

Knowing the value of inductance in an LR series circuit is important for understanding the behavior of the circuit and predicting how it will respond to changes in current or voltage. Inductance plays a crucial role in filtering and regulating the flow of current in many electronic devices, making it an essential factor in circuit design and troubleshooting.