"True Sine" comes from the sales department.
Solid state electronics can NEVER produce a true sine wave. It's solid state!
The sales liturature is alluding to some attempt at replicating a rock-steady 60Hz output with nominal sine characteristics, nothing more.
Since there are no absolute standards as to what constitutes a true enough sine wave, the marketing departments throw the term around pretty loosely.
Your best bet is to salvage ferrite rings from a power supply. Such devices are parked out on the curb every day of the week: abandoned TV sets -- particularly the prior generation of high power, wide screen dimensions.
You'll find that not only are these give-aways... but that each one is stuffed with ferrite rings in the bowels of the power supply.
Just be sure to bleed off the capacitors, first.
( The ferrite rings are used precisely because they clip off high voltage spikes, BTW.)
Impedance in a ferrite ring is an explicit reference to its INDUCTANCE. Capacitance and resistance are zero for such devices.
Adding inductance affects reactive power demand -- and thus 'chokes' the net power delivered. Unless you've ganged up quite a few, this effect is going to be trivial and inconsequential. You're only clipping off the high frequency spikes.
Last edited by Tesla; 05/25/14 05:07 PM.