How do they work - is there a crystal or a transformer to generate the
high voltage?
Taking the easy bits of the hob apart - removing the plate with the
taps, all I can see is the battery holder, the underside of the switch
which is ok, and the 'spark plug' by each of the four burners.
I've cleaned them and fitted a new battery, but it still doesn't work.
Is there something else, maybe below the burner that I need to loook
at?

Thanks

Tony