In the first video, it introduces the principles and terminology of mechanical electrical switches. It covers terms such as contacts, normally open, normally closed, poles, and throws.
The second describes toggle switches, including different configurations and terminology. You'll learn how to apply them in a circuit and why they are one of the safest sitches.
The third describes pushbutton switches and selector switches, including different configurations and terminology. You'll see how they configure into an electric circuit and see the internal spring mechanism.
The fourth, control switches such as limit switches, proximity switches, flow switches, pressure switches, temperature switches, and speed switches.
And lastly, you'll see the importance of contacts in electrical switches. It describes the effects of arcing and contamination on switch operation. It also shows the effects of high voltage arcs and the danger of arc blasts.