Are those textbook field lines?

The primary display is an arrow grid of E at sample points (direction and relative strength). Optional streamlines are short traces along E from seed points near charges — useful intuition, not a density-coded field-line map from a textbook.

How are equipotentials drawn?

Equipotentials are contour levels of the Coulomb potential V = Σ kq/r (k absorbed into relative q), extracted with marching squares on a grid. Near point-charge singularities the potential is masked when choosing level ranges.

What happens when I add several charges?

E and V at each point follow superposition: the total is the sum of contributions from every charge. That is why dipole, quadrupole, and plate-pair patterns emerge from simple vector (and scalar) addition.

Electric Field Visualizer

Place charges and watch the E arrow grid, streamlines, and equipotentials update in real time.

About this model

Point charges in 2D with a Coulomb arrow-grid (vector field) of E, optional sample streamlines, and equipotential contours of V. Add, select, move, edit, or delete charges and drag a positive test probe.

Who it's for: E&M intro; visualizing superposition of fields and symmetry.

Key terms

Coulomb’s law
electric field
superposition
vector field
equipotential
point charge

How it works

Point charges in the plane (Coulomb model). The canvas shows an arrow grid of the electric field E⃗ (vector sum of qᵢ r̂ᵢ/rᵢ²; k absorbed into relative q) plus optional sample streamlines and equipotential contours of V. Arrows point the way a positive test charge would be pushed — this is a vector-field view, not a full textbook field-line density map.

Key equations

E⃗ = Σ k qᵢ r̂ᵢ / rᵢ² (here k absorbed into relative q)

V = Σ k qᵢ / rᵢ · equipotentials: V = const (marching squares)

Frequently asked questions

Are those textbook field lines?: The primary display is an arrow grid of E at sample points (direction and relative strength). Optional streamlines are short traces along E from seed points near charges — useful intuition, not a density-coded field-line map from a textbook.
How are equipotentials drawn?: Equipotentials are contour levels of the Coulomb potential V = Σ kq/r (k absorbed into relative q), extracted with marching squares on a grid. Near point-charge singularities the potential is masked when choosing level ranges.
What happens when I add several charges?: E and V at each point follow superposition: the total is the sum of contributions from every charge. That is why dipole, quadrupole, and plate-pair patterns emerge from simple vector (and scalar) addition.

Continue with similar topics in this category — or all 65 in Electricity & Magnetism.

View category →

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Electric Field Visualizer

About this model

How it works

Key equations

Frequently asked questions

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About this model

How it works

Key equations

Frequently asked questions