---
title: "Discharge electrode"
description: "The discharge electrode (also called the emitting electrode) is the high-voltage element inside an electrostatic precipitator that generates the corona discharge. It is energised at 40–80 kV DC negative relative to the grounded collecting electrodes."
canonical_url: "https://sylio.co/glossary/discharge-electrode"
last_updated: "2026-06-28T02:29:30.412Z"
---

The **discharge electrode** (also called the **emitting electrode**) is the high-voltage element inside an [electrostatic precipitator](/glossary/electrostatic-precipitator) that generates the [corona discharge](/glossary/corona-discharge). It is energised at 40–80 kV DC negative relative to the grounded [collecting electrodes](/glossary/collecting-electrode).

## Geometry

Two families dominate:

- **Wire electrodes** — fine spiral or barbed wires, typically weighted at the bottom and suspended from a top frame. Lightweight; easy to retrofit; prone to fatigue and breakage under [rapping](/glossary/esp-rapper) impacts.
- **Rigid discharge electrodes (RDE)** — pipe or mast sections with formed spikes or points. Used in modern American-style and rigid-frame ESPs. More robust against rapper breakage but heavier.

## Fouling on discharge electrodes

Just like the collecting plates, discharge electrodes accumulate dust. A thick coating on a wire or RDE reduces the local field gradient, suppresses corona, and lowers collection efficiency. The cleaning challenge is geometrically harder than for plates — discharge electrodes are point or line sources surrounded by gas. [Sonic horns](/glossary/sonic-horn) addressing the whole field volume help dislodge dust from discharge electrodes as well as from plates.

## Related terms

- [Electrostatic precipitator](/glossary/electrostatic-precipitator)
- [Collecting electrode](/glossary/collecting-electrode)
- [Corona discharge](/glossary/corona-discharge)
- [Back-corona](/glossary/back-corona)
- [Sonic horn](/glossary/sonic-horn)