Follow the explanation
Back to the model ↑How the parts work together
Light becomes an electric current
Face the panel directly into full sunlight. The 60 cells deliver 216.2 W to the fixed 5 Ω load in this ideal model: 32.88 V and 6.58 A. Reduce sunlight or tilt the panel and the incident light, current and power fall. The moving amber marks are a light cue, not a photon-rate calculation.
Series cells add voltage but share current
Open the layer stack. Glass and encapsulant protect the cells; the rear layers insulate them. The magnified p–n inset names the two doped silicon regions. The panel has three strings of 20 series cells: within each string, every cell carries the same current while their voltages add.
A bypass protects the working strings
Cell A01 is now fully shaded. With its ideal bypass conducting, string A contributes 0 V and the other two strings deliver 104.3 W to the same load. Switch the bypass diodes off: this ideal circuit has no valid forward operating point and output becomes 0 W. Real modules have losses and reverse-behavior that this comparison deliberately omits.
The main parts
- 60 silicon cells
- Sixty clipped-corner silicon wafers in three 20-cell series strings. Cell A01 is the one covered by the shade control.
- Glass & front encapsulant
- A transparent front sheet and encapsulant protect the cells while admitting light. Their thicknesses are enlarged for the layer view.
- Rear encapsulant & backsheet
- Rear layers support and insulate the cell laminate. The model does not calculate weathering or insulation strength.
- Aluminium frame
- Four joined rails surround the laminate and give the panel a recognizable rigid edge.
- Cell busbars & string interconnects
- Two silver busbars on each cell represent the conductive collection paths. The circuit card makes the three series strings explicit.
- Rear junction box
- A protective box on the back joins the strings to the output cable and houses the three illustrated bypass paths.
- Three ideal bypass diodes
- One ideal diode is connected across each 20-cell string. In this model it clamps a reverse-biased string at 0 V; real diode loss and heat are omitted.
- p-type silicon
- Boron-doped silicon has electron vacancies called holes. In the magnified inset it forms the base side of the teaching junction.
- n-type silicon
- Phosphorus-doped silicon contributes free electrons and forms the light-facing emitter in this teaching junction. The inset is symbolic and greatly magnified, not a thickness-scale fabrication drawing.
Questions worth exploring
How does a solar cell make electricity?
A silicon cell contains p-type and n-type regions. Light frees charge carriers and the p–n junction separates them, allowing current to flow through an external circuit. The panel converts light directly to electrical energy; it does not need a spinning generator. The magnified junction in this lesson is a symbolic teaching view, not a fabrication-scale drawing.
U.S. DOE · PV Cells 101: A Primer on the Solar Photovoltaic Cell (semiconductor conversion, contacts and modules)OpenStax · University Physics Volume 3 · 9.6 Semiconductors and doping
Why can one shaded cell reduce a solar panel's output?
Cells in a series string carry the same current. A shaded cell produces less photocurrent, so it can limit every healthy cell in that string even though they remain lit. In this ideal fixed-load model, a fully shaded cell blocks the string completely when no bypass or reverse-breakdown path is available.
What does a bypass diode do in a solar panel?
In this lesson's ideal circuit, a bypass diode turns on when its 20-cell string becomes reverse-biased. It gives panel current a route around that string, so the other two strings can keep delivering power. The model clamps the bypassed string to 0 V and omits real diode voltage loss, heating and reverse breakdown, so it is not a hot-spot or reliability simulation.
Why does solar-panel tilt matter?
Tilting a flat panel away from the incoming rays reduces the area it presents to them. This model uses direct irradiance proportional to the cosine of the tilt angle: 60° gives half the face-on value. It omits diffuse sky light and reflections, so it is a geometric demonstration rather than an energy-yield forecast.
U.S. DOE · Tribal Energy Webinar: Solar & Wind (plane-of-array direct-beam cosine)