Lighted switch on switch loop?

I was changing out a lighted switch yesterday and found it odd that it is actually just a switch loop, with no neutral. The switch is not solar powered, so what is powering the light if just the hot is running to it?

 

The neutral is at the light fixture.

The light in the switch is across the terminals of the switch. When the switch is off there is voltage from the hot through the switch-light and to neutral through the light fixture. The light fixture draws enough current to excite the neon in a small bulb but the current is limited. There is often a resistor in series with the small neon bulb.

The switch light goes out when the switch is on.

 

I have just replaced all of these in my house. Which is a shame because they looked great.

The reason is that the small amount of current draw needed to light the light makes many brands (but not all) of fluorescent (CFL) lights flicker.

It just goes to show that when it comes to switches, it's hard to beat the old design.

I changed them out because if a home inspector saw a flickering light, you'd probably suggest a short.

 

If there was a short, then the breaker would trip, but as for the flickering light in the lightswitch, it would just mean that the bulb in the switch is near its life end, not the bulb in the fixture.