Capacitor Self-Resonant Frequency

f_SRF = 1 / (2π × √(ESL × C))

Quick answer

This calculator solves f_SRF = 1 / (2π × √(ESL × C)) for Self-Resonant Freq. With Equiv. Series Inductance 10 nH, Capacitance 100 nF, the result is 5.033 MHz. It solves in 3 directions, so you can enter the values you have and get the one you need.

Calculator

Self-Resonant Freq (MHz)
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Formula

f_SRF = 1 / (2π × √(ESL × C))

Description

Every real capacitor has parasitic equivalent series inductance (ESL) from its leads, internal connections, and electrode geometry. At the self-resonant frequency, the capacitive reactance (1/ωC) exactly cancels the inductive reactance (ωL), and the impedance reaches its minimum (equal to ESR). Below the SRF, the component behaves as a capacitor; above the SRF, it behaves as an inductor. This frequency determines the useful bandwidth of a capacitor for decoupling and filtering applications.

Variables

  • f_SRF — Self-resonant frequency (Hz)
  • ESL — Equivalent series inductance (H)
  • C — Capacitance (F)

Practical Notes

Typical ESL values: through-hole ceramic 2-5 nH, SMD 0805 about 1 nH, SMD 0402 about 0.5 nH. A 100 nF 0805 ceramic has SRF ≈ 16 MHz with 1 nH ESL. For effective decoupling above the SRF, place a smaller capacitor (e.g., 100 pF) in parallel. Always check that your operating frequency is well below the SRF of your decoupling capacitors.

Symbols and units

Symbol Meaning Default unit Accepted units
fSRF Self-Resonant Freq MHz Hz, kHz, MHz, GHz
ESL Equiv. Series Inductance nH nH, µH, mH, H
C Capacitance nF pF, nF, µF, mF, F

Step by step

  1. 1. What you know: Equiv. Series Inductance 10 nH, Capacitance 100 nF
  2. 2. The relation: f_SRF = 1 / (2π × √(ESL × C))
  3. 3. Substitute: ESL = 10 nH, C = 100 nF
  4. 4. Result: Self-Resonant Freq = 5.033 MHz

Worked examples

Minimum range

Given: Equiv. Series Inductance 0.1 nH, Capacitance 100 pF

Result: Self-Resonant Freq = 1.592 GHz

Low range

Given: Equiv. Series Inductance 1 nH, Capacitance 1 nF

Result: Self-Resonant Freq = 0.1592 GHz

Typical

Given: Equiv. Series Inductance 10 nH, Capacitance 100 nF

Result: Self-Resonant Freq = 5.033 MHz

High range

Given: Equiv. Series Inductance 100 nH, Capacitance 1 µF

Result: Self-Resonant Freq = 0.5033 MHz

Maximum range

Given: Equiv. Series Inductance 1 µH, Capacitance 10 µF

Result: Self-Resonant Freq = 50.33 kHz

Solving for each variable

Solve for Self-Resonant Freq

Equiv. Series Inductance 0.1 nH, Capacitance 100 pF → 1.592 GHz

Solve for Equiv. Series Inductance

Self-Resonant Freq 100 kHz, Capacitance 100 pF → 25.33 mH

Solve for Capacitance

Self-Resonant Freq 100 kHz, Equiv. Series Inductance 0.1 nH → 25.33 mF

How Self-Resonant Freq changes with Equiv. Series Inductance

Equiv. Series Inductance (input) Self-Resonant Freq (result)
1 nH 15.92 MHz
2.5 nH 10.07 MHz
5 nH 7.118 MHz
7.5 nH 5.812 MHz
10 nH 5.033 MHz
15 nH 4.109 MHz
20 nH 3.559 MHz
40 nH 2.516 MHz
70 nH 1.902 MHz
100 nH 1.592 MHz

The same result in other units

Unit Value
Hz 5033000
kHz 5033
MHz 5.033
GHz 0.005033

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Frequently asked questions

How do you calculate Capacitor Self-Resonant Frequency?

Use f_SRF = 1 / (2π × √(ESL × C)). With Equiv. Series Inductance 10 nH, Capacitance 100 nF, Self-Resonant Freq works out to 5.033 MHz.

Which 0402 capacitor value has a 1ghz self resonant frequency?

Rearrange for Self-Resonant Freq: with Equiv. Series Inductance 1 nH, Capacitance 1 nF, Self-Resonant Freq is 0.1592 GHz.

How do you calculate self resonant frequency for 0402 0.1uf capacitor?

Rearrange for Self-Resonant Freq: with Equiv. Series Inductance 10 nH, Capacitance 100 nF, Self-Resonant Freq is 5.033 MHz.

What is the formula for Capacitor Self-Resonant Frequency?

The formula is f_SRF = 1 / (2π × √(ESL × C)). Every real capacitor has parasitic equivalent series inductance (ESL) from its leads, internal connections, and electrode geometry.

How do you find Equiv. Series Inductance when you know the other values?

Rearrange for Equiv. Series Inductance: with Self-Resonant Freq 100 kHz, Capacitance 100 pF, Equiv. Series Inductance is 25.33 mH.

How do you find Capacitance when you know the other values?

Rearrange for Capacitance: with Self-Resonant Freq 100 kHz, Equiv. Series Inductance 0.1 nH, Capacitance is 25.33 mF.

Related Concepts

All Capacitors formulas →
Capacitive Reactance RC Time Constant Capacitor Energy Capacitor Charge Series Capacitance Parallel Capacitance Capacitor Impedance with ESR Capacitor Self-Resonant Frequency

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