exemplary starting circuit for excitation of starter probe 12 comprises a resonant lc circuit of variable impedance including the series combination of a variable inductance provided by starting coil 14 in the embodiment of fig1 and the parasitic capacitance between the starter probe and the excitation coil such a starting circuit is described in u s pat no 5 057 750 cited hereinabove other suitable resonant starting circuits are described in commonly assigned u s pat no 5 103 140 of j p cocoma and g a farrall issued apr 7 1992 and commonly assigned u s pat no 5 118 996 of s a e1 hamamsy j p cocoma and g a fartall issued jun 2 1992 both of which patents are incorporated by reference herein in accordance with the present invention the starting circuit further includes a visible light radiator 40 shown in fig1 as a light emitting diode led a resistor 42 is shown as being coupled in series with led 40 and the other terminal of led 40 is coupled to the starting circuit ground potential also shown in fig1 is a light guide 44 e g comprising a quartz rod for coupling the light from led 40 to starting chamber 32 and also for protecting led 40 from heat generated by starter probe 12 and lamp 10 led 40 resistor 42 and quartz rod 44 are mounted onan insulator 46 e g comprising a laminated phenolic rod such as for example bakelite manufactured by union.