How to recognize different voltage sources for electricity

This is a recording of a class lecture on Voltage Sources. The first part describes how mechanical friction can generate voltages.

The second describes how current can be generated using magnetism and from the energy of light.

The third part describes how current can be generated using heat and pressure.

The fourth describes how current can be generated using chemical energy in cells and batteries.

And the last describes how current can be generated using chemical energy in cells and batteries. It also describes fuels cells, and how cells and batteries can be connected in series for more voltage, parallel for more current capacity, and series-parallel for increases current and voltage.