Physics
Capacitor lab
Compare a parallel-plate field solver with an ideal coaxial capacitor. Move a probe through the radial field; hold voltage or isolate charge.
What happens
Parallel plates use a numerical field solver, including edge fields. Drag the plates or dielectric and compare charge, voltage, energy and force. Coaxial mode uses the analytic solution for long concentric cylinders with a uniform dielectric; end fields are omitted. Click the cross-section to move the radial probe. Disconnect the battery to hold Q fixed, or connect it to hold V fixed.
Equations used in the module
Equations C = ε₀ ε_r A / d, Q = C V E = V / d, U = ½ C V² = Q² / (2C) I = dQ/dt Coax: C = 2π ε₀ εᵣ L / ln(b/a) Eᵣ = V / [r ln(b/a)], a < r < b V(r) = V ln(b/r) / ln(b/a)
