Mechanically controlled inverters are a lot easier to make than electronic ones for most people, as most don't have electronics skills. These use an electromagnetic oscillator to drive a transformer. Large inverters can use half mains frequency to simplify design, at the expense of more iron in the transformer.
These simple inverters are unregulated and not accurately frequency controlled. However theyre plenty good enough for some tasks, such as running motors (a lot but not all) and power tools, or CFL/fluorescent lighting. Its also possible to add a tap changer to almost stabilise output voltage.
The reason I suggest this as an option is simply that electronics skills are in short supply, whereas any mechanical tinkerer can put these inverters together and use them to run tools, lighting, some appliances etc. 22.214.171.124 09:11, 19 March 2010 (UTC)