An electronic device that allows current to flow in one direction only.

A tube with two electrodes in which the main use of diodes is to keep the electric current flowing in one direction.

A semiconductor connected in series with a solar cell or cells and a storage battery to keep the battery from discharging through the cell when there is no output, or low output, from the solar cell.

It can be thought of as a one-way valve that allows electrons to flow forwards, but not backwards.

A diode connected across one or more solar cells in a photovoltaic module such that the diode will conduct if the cell(s) become reverse biased.

It protects these solar cells from thermal destruction in case of total or partial shading of individual solar cells while other cells are exposed to full light.

A semiconductor device with a junction and a built-in potential that passes current better in one direction than the other. All solar cells are junction diodes.