Capacitance Converter
Convert Farads, Microfarads, Nanofarads, and Picofarads.
Typical Capacitors
| Type / Usage | Value Range | Application |
|---|---|---|
| Supercapacitor | 1 F - 5000 F | Energy Storage |
| Electrolytic | 1 µF - 4700 µF | Power Supply Filter |
| Ceramic | 1 pF - 0.1 µF | High Frequency |
| Earth (Planet) | ~710 µF | Theoretical |
What is Capacitance?
Capacitance is the ability of a system to store an electric charge. It is the ratio of the change in electric charge to the corresponding change in its electric potential.
Unit Explanations
Farad (F)
The SI unit of capacitance. It is a very large unit, so sub-multiples are commonly used.
Microfarad (µF)
One millionth of a Farad. Common in household electronics and motors.
Picofarad (pF)
One trillionth of a Farad. Used in radio frequency (RF) circuits and timing applications.
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Storing Energy in an Electric Field
Capacitors are one of the three fundamental passive components in electronics (alongside resistors and inductors). They store energy in an electric field, created by accumulated charge on two conductive plates. This property, capacitance, is measured in Farads.
From tiny picofarad capacitors filtering radio-frequency noise to massive Farad-scale supercapacitors powering electric buses, understanding capacitance conversions is essential for any electronics work.
The Farad (F)
The Farad (symbol: F) is the SI unit of capacitance. It is defined as:
A Farad is an enormous amount of capacitance. Most capacitors you encounter are measured in µF, nF, or pF.
Common Unit Prefixes
Capacitor Types & Applications
Different capacitor technologies suit different applications:
Polarized. Power supply filtering, audio coupling. High capacitance/volume.
Non-polarized. Decoupling, RF bypass. Tiny SMD packages.
Stable, low ESR. Audio, motor run, snubbers.
Polarized, stable. Compact, used where space is limited.
Massive energy storage. Backup power, regenerative braking.
Extremely stable, low loss. RF oscillators, precision circuits.
⚡ The RC Time Constant
When a capacitor charges through a resistor, the time it takes is described by the RC time constant (τ = R × C). After one time constant, the capacitor reaches 63% of its final voltage.
For example, a 10kΩ resistor and a 10µF capacitor give τ = 10,000 × 0.00001 = 0.1 seconds. This is fundamental to timing circuits, filters, and debounce logic.
Frequently Asked Questions
What is Capacitance?
Capacitance is the ability of a component to store electrical energy in an electric field. A capacitor is a device designed to hold capacitance. It consists of two conductive plates separated by an insulator (dielectric). When voltage is applied, charge accumulates on the plates, storing energy.
What is a Farad (F)?
The Farad (F) is the SI unit of capacitance, named after Michael Faraday. 1 Farad is achieved when 1 Coulomb of charge causes a 1 Volt potential difference across the capacitor. A Farad is an extremely large unit—most practical capacitors are measured in microfarads (µF), nanofarads (nF), or picofarads (pF).
How do I convert Microfarads (µF) to Picofarads (pF)?
Since 1 µF = 1,000,000 pF (10⁶), simply multiply the µF value by 1,000,000. For example, 0.1 µF = 0.1 × 1,000,000 = 100,000 pF (or 100 nF). Conversely, divide pF by 1,000,000 to get µF.
What is the difference between µF, nF, and pF?
These are just scale prefixes: µF (Microfarad) = 10⁻⁶ F (one millionth), nF (Nanofarad) = 10⁻⁹ F (one billionth), pF (Picofarad) = 10⁻¹² F (one trillionth). Note: 1 µF = 1,000 nF = 1,000,000 pF.
What is a Supercapacitor (Ultracapacitor)?
A supercapacitor (or ultracapacitor) is a capacitor with very high capacitance (measured in Farads, not microfarads!), typically 1F to 3000F. They can store much more energy than regular capacitors but less than batteries. They are used for backup power, regenerative braking, and burst-power applications.
Why do capacitors have a voltage rating?
The voltage rating indicates the maximum voltage the capacitor can handle before its insulating dielectric breaks down, which causes permanent damage or explosion. Always choose a capacitor rated for at least 1.5x - 2x your expected operating voltage for safety.
What is the EIA capacitor code (103, 104)?
Small ceramic capacitors often use a 3-digit code. The first two digits are the value, and the third is the multiplier (number of zeros). For example, 104 = 10 × 10⁴ = 100,000 pF = 100 nF = 0.1 µF. Similarly, 103 = 10,000 pF = 10 nF.
What are Electrolytic vs. Ceramic capacitors?
Electrolytic capacitors offer high capacitance (µF to mF range), are polarized (must be connected correctly), and are used for power filtering. Ceramic capacitors are smaller, non-polarized, and used for decoupling and high-frequency applications (pF to low µF range).
How do capacitors behave in Series vs. Parallel?
In Parallel, capacitances simply add up (C_total = C1 + C2...). In Series, the total capacitance decreases: 1/C_total = 1/C1 + 1/C2... This is the opposite behavior of resistors!
What is an RC Time Constant?
The RC time constant (τ) describes how long a capacitor takes to charge or discharge through a resistor. τ = R × C. After one time constant, the capacitor reaches 63% of full charge. After 5τ, it is considered fully charged (99%).