LC Resonance Calculator

This calculator helps us to:

• Find the resonant frequency if we know the capacitance and inductance values.
• Or find the capacitance if we know the frequency and inductance.
• Or find the inductance if we know the frequency and capacitance.

What is LC Resonance

So LC resonance happens when we connect a capacitor (C) and an inductor (L) together in a circuit either in series or in parallel. This thing starts to behave like a kind of natural oscillator. It keeps charging and discharging energy between the capacitor and coil, back and forth like a swinging pendulum.

That swinging frequency where this energy goes round and round perfectly, is called the resonant frequency.

At this point both C and L cancel out each other’s reactance and the circuit allows signals to pass super efficiently at that one special frequency.

Breakdown:

• Capacitor stores energy as electric field.
• Inductor stores energy as magnetic field.
• When you connect them, one throws the energy to the other and back again.
• This creates a natural oscillation at one fixed frequency.

How to Use This Calculator

So just do this step-by-step:

Step 1: Choose what you already know

Like:

Do you already have a capacitor and coil? Then pick:

• Value 1: 0.1
• Unit 1: Capacitance (µF)
• Value 2: 10
• Unit 2: Inductance (µH)

Or maybe:

You want a frequency of 100 kHz and you have a 0.01 µF cap? Then do:

• Value 1: 100000
• Unit 1: Frequency (Hz)
• Value 2: 0.01
• Unit 2: Capacitance (µF)

Step 2: Press "Calculate Unknown" button

Then it will show:

• If you gave L and C, it gives you Frequency.
• If you gave f and L, it gives you Capacitance.
• If you gave f and C, it gives you Inductance.

What Formula It Uses

Here is the main thing, this calculator uses this famous LC resonance formula:

f = 1 / (2π√(L × C))

Where:

• f is frequency in Hertz.
• L is inductance in Henry.
• C is capacitance in Farad..

It rearranges this formula based on what values you give.

For example:

• If you want to find C then:

C = 1 / (4π²f²L)

If you want to find L then:

L = 1 / (4π²f²C)

Units Supported:

You can manually convert other units like nF or mH outside if needed.

Tips & Notes to Remember

• Always give only 2 inputs, so 3rd one will be calculated.
• Never give both inputs of the same type (like Cap and Cap)... it will show error.
• If your result comes in exponential (like 2.3e-7 F) then that means it is very small value, just multiply and convert:
  • Example: 2.3e-7 F = 0.23 µF
• Capacitance values usually go in µF, nF, or pF.
• Inductance values are in µH or mH for small coils.
• Use ceramic or film caps for high freq LC tanks.
• Avoid electrolytic caps in resonance circuits.