Partial Shading & Hotspots in a Solar Panel (2D)

Solar cells in a panel are wired in series, so the whole string can only carry as much current as its weakest cell. This 2D canvas simulator models an 18-cell string with a real single-diode equation per cell, lets you click individual cells to shade them, and shows exactly what happens electrically: a shaded cell is forced into reverse bias by the healthier cells around it and starts dissipating power as heat instead of generating it — the physical origin of solar-panel hotspots, with the live I-V curve drawn from the same equation. Toggle the three per-row bypass diodes to see how real panels prevent this by routing current around a shaded row, at the cost of losing that row's output.