Inverters, Sine Wave?

Hey Jimbo, pure sine wave is for delicate electrical equipment (eg) medical equip, scientific equip, modified is OK for most other items.

Baz.

Hi Ya Jimbo,

I agree. I was also led to believe that "some" Laptops required a pure sign wave to operate, but this was from a manufacturer/distributor of the more expensive type of inverter.

I also have a "cheapie" 300 watt modified sign wave inverter which powers my IBM Thinkpad without any problems whatsoever. Cost me about $130 from JCAR whom also sell the more expensive pure sign wave unit.

The salesperson said "what do you want the expensive one for?"
He said (nice bloke) try the cheaper one and if it doesn't work, we'll refund your money.

Sometimes you do get a helpful dude behind the counter.

I have the same problem gone through 3 invertors over the last 12 months trying to run my toshiba laptop but since I spent $79 and got the laptop 15-22volt one from jaycar no more problem

I was advised to buy a Pure Sinewave inverter for the laptop which I did. The 150watt inverter at a cost of $280 cooked a condensor when I married the laptop to it when running Oziexplorer. My mate fixed the inverter and since then I have bought a Kerio 12v dc laptop power source and it works very well. The inverter still sits there for running a variety of appliances when needed.

Hi Jimbo

I had normal Dick Smith Inverter that was not pure sine wave but a square like me. It worked quite well for a while but my laptop power supply used to get hotter than when at home and it also made a louder buzzing sound when plugged in. After a while it seemed to make the power supply overload and we had to turn it off and wait till things cooled down. I got nervous after hearing about them burning out the notebook power supply and changed to a Jaycar Pure Sine wave inverter and it does not run cooler and quieter.

Andrew

Switch mode power supply's are most likely to be the least affected by a modified sine wave. The people that were told they need a pure sinewave did they tell you why? The first thing a switch mode supply does to the incoming 240V is fully rectify it and produce DC, then it switches this DC at a rate of approx 30KHz and converts it back to AC before going through a very small transformer to reduce the voltage to what ever is required, then rectified and regulated to produce a very stable regulated DC supply. By the time the incoming 240 AC is rectified then chopped up at 30Khz it really doesn't matter what the incoming AC looked like, whether it was a pure sinewave or a stepped one doesn't really matter. You will get far better results with a switch mode than a conventional iron cored transformer when run from a modified sinewave. The iron cored transformer will become very innefficient with a modified sine wave, it will get hotter and produce less current. The switch mode supply is the one that doesn't weigh much, feels like there's not much in side it.