How Does a Fog Machine Work?

Fog Machine

A fog machine works by making clouds out of a special fluid made of water and glycerine. The liquid gets pulled into the fog machine by a small pump. From there, the liquid moseys over into a heat exchanger which heats the fluid up into a vapor. The vapor continues through a pipe and mixes into a stream of room temperature air, which is cool enough for the glycerine and water mix to condense to form a cloud!

Here is a more detailed description of how a fog machine works by a company that makes them.

Fog machines have come down in price dramatically over the last 5 years or so. Whereas I was looking at paying $100 for a machine in 2000, I just picked up this one for $20 - amazing! Of course, you could build your own, but overheating the fluid could lead to bad chemicals in the air and the mix of water and electricity is an electrocution and fire hazard, so be careful. I made one a long time ago similar to the iron one linked to above, but now it is not even economical to go that route - might as well buy a new one.

Electronics

In this fog machine it looks like they needed low voltage DC power for the pump and the fan, so they put the 120V AC line voltage through a transformer then into a full-wave rectifier made of four diodes and a smoothing capacitor.

(Wikipedia Article For More Info )