# Difference between Capacitor and Reactor

**URL:** <https://forumautomation.com/t/difference-between-capacitor-and-reactor/14292>\
**Category:** Electrical\
**Tags:** basic\
**Created:** [July 31, 2026, 1:56pm UTC](https://forumautomation.com/t/difference-between-capacitor-and-reactor/14292 "2026-07-31T13:56:10Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Rabert](https://forumautomation.com/user_avatar/forumautomation.com/rabert/32/6784_2.png) [@Rabert](https://forumautomation.com/u/Rabert)\
**Post date:** [July 31, 2026, 1:56pm UTC](https://forumautomation.com/t/difference-between-capacitor-and-reactor/14292/1 "2026-07-31T13:56:11Z")

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## Difference between Capacitor and Reactor

**[Capacitors](https://forumelectrical.com/parallel-capacitors-calculator/)** and **[reactors](https://forumelectrical.com/essential-oil-immersed-shunt-reactors-commissioning-checklist/)** are both passive electrical components used in power systems, but they perform opposite functions.

A capacitor stores electrical energy in an electric field and supplies reactive power to improve voltage and power factor.

 ![1 - Copy](https://cdn.forumautomation.com/original/2X/5/5592f19b07c40ca52db5759514f214cf5ff385c7.jpeg)

A reactor (inductor) stores energy in a magnetic field and absorbs reactive power to limit current, control voltage, and reduce harmonics.

## Capacitor vs Reactor Comparison

| **Parameter** | **Capacitor** | **Reactor (Inductor)** |
| --- | --- | --- |
| **Definition** | Stores energy in an electric field | Stores energy in a magnetic field |
| **Main Function** | Supplies reactive power | Absorbs reactive power |
| **Electrical Quantity** | Capacitance (Farad, F) | Inductance (Henry, H) |
| **Symbol** | Two parallel plates | Coil of wire |
| **Reactance Formula** | Xc = 1 / (2πfC) | XL = 2πfL |
| **Frequency Effect** | Reactance decreases as frequency increases | Reactance increases as frequency increases |
| **Current-Voltage Relationship** | Current leads voltage by 90° | Current lags voltage by 90° |
| **Power Factor Effect** | Improves lagging power factor | Reduces leading power factor |
| **Energy Storage** | Electric field | Magnetic field |
| **Power Consumption** | Supplies capacitive VAR | Consumes inductive VAR |
| **Voltage Effect** | Increases system voltage | Reduces or controls system voltage |
| **Current Effect** | Can increase charging current | Limits fault and inrush current |
| **Losses** | Very low dielectric losses | Copper and core losses |
| **Applications** | Power factor correction, voltage support, filtering | Current limiting, harmonic filtering, fault current limitation, voltage control |
| **Common Installation** | Capacitor banks, motors, substations | Series reactors, shunt reactors, harmonic filter reactors |
| **Maintenance** | Inspection for swelling, leakage, and dielectric condition | Inspection for overheating, insulation, winding integrity, and vibration |