How Do You Measure Inductance Without a LCR Meter?

It’s natural that your home will have any sort of electronic devices like a television or a radio. Inductance is something that happens regularly in such machines since there’s a need for the electrical current in them to stop suddenly and switch to another current flow.

This will happen every time you change the channel. This inductance provides us the ability to change channels whenever we want. You can also measure this inductance.

But how do you measure inductance without a LCR meter is something that is a bit tricky. We are here to help you with just that!

How Do You Measure Inductance Without a LCR Meter

We know that inductance is the way a coil stops electrical currents while it is flowing through electronic devices. There are multiple other ways for you to be able to measure inductance in your electronic devices or machines.

A best LCR meter is not necessarily needed for such a task. Below some steps are given:

Step 1: Choosing the Right Resistor to Use

The resistor you need for measuring inductance is the 100 ohm resistor. Make sure it also has about 1 percent resistance. This particular component should have the pattern of brown-black-brown on it since all resistors come with colored bands to make it easier for us to know how much ohm comes from which.

Make sure you choose the resistor that gives you a known resistance value whenever you are stuck choosing from a lot of options.

New resistors will always have labels on them, but the moment you take them out of the packaging, you will not be able to tell them apart anymore. So please make sure to use a resistor that is well known to you if you want to avoid trial and error issues.

Step 2: Connecting the Inductor Coil With the Resistor

Connecting the Inductor Coil With the Resistor

Now that you have bought the right resistor to work with, you just have to connect it with the inductor coil in your electronic device or machine.

Do not forget that it has to be connected in series with your resistor. Here the term ‘in series’ refers to the electrical current passes through the inductor coil one by one serially.

You need to set up a circuit with the inductor coil and resistor by placing them side by side. They have to have at least 1 terminal touching. After that, you need to get power wires and connect them to both the resistor and inductor coil at their exposed ends.

These power wires can be found in any hardware store and come in red and black colors. You need to get one of each. Connect the red power wire to the end of the resistor and the black power wire to the end of the inductor coil.

The holes in a breadboard can also help with connecting the wires with the resistor and coil.

Step 3: Oscillation

For this step, you need to get a function generator along with an oscilloscope. The function generator is a kind of electrical tester. Its task is to send electrical waves throughout your circuit.

You can control the signals that move through the inductor coil and calculate inductance. Also, this equipment shows the change in electrical current waves and detects signal voltage in a circuit.

It displays this data in the form of a line on a monitor or screen. This helps you to visualize the kind of signal you are setting up with your generator. The output lead parts of the function generator have to be plugged into the oscilloscope.

Now you just need to turn on both the devices. While they are running, you need to take the red output lead of the function generator and connect it to the red power wire of your already set up circuit.

In the same way, you need to connect the black input lead of the oscilloscope to the black power wire of the circuit. This way you have wired the function generator and the oscilloscope into the circuit.

Step 4: Running Currents Through the Circuit

The generator will stimulate currents to the inductor and resistor when they are in use. There is a control knob on the device. If you want to start a current flow, then you need to use that knob.

Set up your function generator to about 50 to 100 ohms and have it set to sine waves. This way you can see larger and curvier waves displayed on the monitor or screen.

If you ever want to see a different kind of wave displayed, then you need to go to the function generator’s settings and change it.

Among the various waves a function generator can make, sine, square, triangular, etc. are the common ones. Although most of these types of waves are not necessary to use if you want to calculate inductance.

Step 5: Monitoring the Voltage on the Screen

On the oscilloscope, you can see a display of two sine waves on the monitor. What you mostly need to keep an eye on is the voltages of the input and the resistor. The function generator can help you control the bigger sine wave.

The smaller sine wave is produced from the place the inductor coil and resistor connect. You need to adjust the generator’s frequency so that the junction voltage will decrease to half the size of its original voltage.

The junction voltage here means the difference between the two sine waves on the screen of the oscilloscope.

Step 6: Finding the Right Frequency

The frequency on the generator’s current that you need to find should be displayed on the screen of the oscilloscope. You just need to look at the number on the readout’s bottom area and look for the one that is in kilohertz (kHz).

Note down this number as you may need it for calculating the inductance. The formula of converting Hertz (Hz) to kilohertz (kHz) is given below:
1 kHz = 1000 Hz
Or 1 Hz = 0.001 kHz

Step 7: Making Calculations of the Inductance

You need to use mathematical formulae for this step. The formula you need to use is given below:
L = R *

Here, ‘L’ is the inductance we are looking for. For this, you need ‘R’ which is the resistance, and ‘f’ which is the frequency.

After you multiply the resistor with the square root of 3, you need to multiply the frequency with 2 and pi which is approximately 3.1416. The resistor will be the number of ohms while the frequency is the number of kilohertz.

Divide the numerator with the denominator and the answer will be revealed in millihenries (mH) since that is how inductance is calculate to using a LCR meter.

You can then convert the millihenries into microhenries (uH) by following the measurement below:
1 millihenry (mH) = 1000 microhenry (uH)

So, if you got, let’s say, 1.378 millihenries of inductance, then it will become 1378 microhenries.

Final Words

There are various calculators or software programs you can use to calculate the inductance. But you still need to go through finding out the amount of resistance and frequency coming from a circuit you set up.

Knowing the answer to the question- ‘how do you measure inductance without a LCR meter’ seems like a lengthy process but it is still very interesting since you now get to see what happens when you are idly relaxing and switching channels on your television or radio.

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