Pure Sine Wave (PSW) Inverters fall into 2 different categories; high voltage/high frequency and low voltage/low frequency.
The high voltage type has two sections. The first section s converts the incoming DC into a high voltage, high frequency AC square wave. They use MOSFET transistors and smaller transformers. This is then converted back to high voltage DC (close to 200V). This is then sent to the final stage where it is convert into 120V AC. These tend to be less expensive, because they use smaller transformers (less iron, less copper).
The low voltage and low frequency inverters convert the incoming DC directly into low voltage AC. This is then feed to a large transformer (these look like a big donut).
The first style tend to be less expensive, but for reasons I do not understand, these tend to have more failures, especially for high power inverters (>1500W).
The interesting footnote is a Chinese semiconductor company invent a single chip that does the hard work of making the AC signal in BOTH styles of inverters. This part is CHEAP !
Actually, most of the parts inside of an inverter are not that expensive except for the transformer(s) and the heat sinks and case. "Good" MOSFET transistors are less than $2 in quantity. The "best" maybe >$10 and do make for a slightly more efficient inverter. There are eBay seller who are selling all the parts your need, minus the transformer and case and wiring for a 2000W invert for <$100 !
The point I am trying to make is, I think some of the "brand name" inverters out there are grossly over-charging because of their name or because they are using designs that are >10 years old.
Anything <1000W is fairly "light duty" so going with a cheaper one is probably a risk worth taking.
WZRELB Reliable Power Inverter 800W Amazon $136
