All your examples are correct. In general, 'switch on' (and 'switch off') can be used in any context that involves electricity or electronics. It's directly related to the noun 'switch', of course, which is a device for connecting and disconnecting an electric power source. 'Turn on' and 'turn off' can also be used in electrical contexts. They come from the earlier days of electrical devices when controls often had to be turned rather than pressed to operate the equipment, but we still use them for modern switches. 'Turn on' and 'turn off' can also be used for water sources, such as taps. Obviously, this is because a turning motion is used to open and close the tap. Clearly, we can't use 'switch on' and 'switch off' in this context.