[Osem]

There are various types of electric hob: flat solid plates, those with spiral like metal elements and those with a smooth ceramic top and some form of concealed element (halogen or similar) underneath - the latter being the most modern. Induction hobs are much more expensive and emit no heat whatsoever, instead they rely on strong magnetic fields to agitate the molecules in the base of ferrous pans which causes them to heat rapidly and thereby cook the contents.

Unless the you have the same fault with both of the 2 larger rings you use (unllikely I'd have thought) it would appear that the pans are to blame. Cheap and/or thin pans (even stainless steel ones) don't distribute the heat effectively and tend to create hot spots which can cause some parts of the food to be burned and others to be undercooked. That'd be my guess for what's wrong and the easy way to find out would either be to try a better pan from somewhere or use your pans on someone else's hob and see what happens.

HTH.