What the coil does
The question we get most often is «what does it actually do?». Short answer: it makes a weak rotating electrostatic field around itself. Then comes the long part — how exactly, what it depends on, and what you can do with it.
The signal
The generator feeds the coil a sine wave. Not a pulse, not a square wave — a sine specifically: it has no sharp edges and does not heat the wire with unnecessary harmonics. The frequency comes either from the device's own generator or from an app on your phone through a 3.5 mm jack.
Our devices work in the audio range, roughly 100 Hz to 20 kHz. These are not radio frequencies: the field does not travel far and does not pass through walls. Half a metre away the field tester already shows almost nothing.
The winding
This is where the models start to differ.
A flat disc wound as a spiral gives a field concentrated in the plane of the disc. A torus wound as a 12- or 14-point star gives a more complex picture: the turns cross at an angle and the field gains a pronounced axis through the centre. More rays means a denser winding and a finer structure.
This is not a metaphor. Take the tester from the box, move it around the disc and then around the torus — the readings differ both in magnitude and in where the maximum sits.
What you can measure yourself
The build is open on purpose: the winding is visible, the terminals are exposed, nothing is potted in compound.
If your numbers disagree with ours, write to us. We keep a measurement log for every series and we are genuinely interested in comparing.
What the coil does not do
It does not treat. It does not diagnose. It does not replace a doctor. It is a device for experiments and that is exactly how we sell it.
The field it makes is weak — considerably weaker than anything a physiotherapy machine in a clinic produces. If someone promises you a clinical effect from a coil like this, ask what they measured it with.
Where to start
Never held a signal generator before? Take the kit with the timer: everything is in the box, including the field tester and a 60-page manual.
Got an oscilloscope and the urge to dig in? Take a bare coil and drive it from your own source. On request we wind to a different pitch, diameter and connector.