Point-charge Electric Field
Compute electric field E of a point charge Q (µC) at distance r (k=8.99×10⁹).
Inputs
Formula
E = k·Q/r²
Field strength guides insulation and ESD protection.
Fundamentals
Compute electric field E of a point charge Q (µC) at distance r (k=8.99×10⁹).
This tool computes Point-charge Electric Field from the formula: E = k·Q/r²
History
Design theory of gears, threads and bearings matured with machine tools and standardisation (AGMA, ISO) since the Industrial Revolution.
Engineering applications
Used for transmission design, joint strength checks and component selection.
Glossary
| Charge Q | Input parameter |
| Distance r | Input parameter |
| Field E | Output result |
How to use
- Fill in Charge Q, Distance r in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Field E in the results area.
Formula · Worked Example · Knowledge
Formula
核心计算关系：E = k·Q/r²
输入变量：
- Charge Q
Q— µC - Distance r
r— m
输出结果：
- Field E
E— kV/m
假设/适用：Gearing/thread formulas assume standard, zero-backlash mounting; include error & load factors K_A.
Worked Example
根据公式 E = k·Q/r²，取 Charge Q = 1 µC；Distance r = 0.1 m。
代入计算得：Field E = 899 kV/m。
Key Points
- Gearing/thread formulas assume standard, zero-backlash mounting; include error & load factors K_A.
- Compare stress with allowable stress and keep a safety factor (≥1.5, ≥2 for critical parts).
- For high speed/load also check lubrication, heat and fatigue life, not just static strength.
Parameters
Inputs
| Parameter | Symbol | Unit | Default |
|---|---|---|---|
| Charge Q (µC) | Q | µC | 1 |
| Distance r (m) | r | m | 0.1 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Field E | E | kV/m |
Applications
- Common engineering use cases
FAQ
What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: E = k·Q/r²
How accurate are the results?
Results match input precision, based on SI units and common engineering approximations; for critical duty re-check with a safety factor.
Where is it used?
Common engineering use cases