separated by means of a layer of semi conductor material 22 further support and electrical isolation between the inner and outer electrodes adjacent the ignitor tip is provided by a ceramic disc 24 and the interior of electrode 20 in those areas not taken up by ceramic disc 24 and semi conductor 22 will be filled with a suitable insulating material such as an epoxy resin as indicated at 26 the burner 10 also includes means for supplying 34 secondary 34 air to the ignition zone about the feed pipe 12 the secondary air passage is indicated at 30 and includes a flow control damper in the burner shown in the drawing the damper is indicated at 32 and through manipulation of adjustment arms 34 the secondary air flow may be varied between the full flow and the completely off conditions the secondary air passage 30 includes a plurality of vanes not shown which are arranged to impart a swirl to the air which is of course delivered to passage 30 from a pressurized air supply also not showh the secondary air passage 30 terminates in a divergent nozzle 36 the burner 10 also includes an annular shaped auxiliary air nozzle 38 air will be flowing through the auxiliary air nozzle at the time of ignition in accordance with the present invention the means for establishing a sufficient potential difference between the electrodes 18 and 20 to cause the air in the vicinity of the ignitor tip to ionize and an arc to be established includes a step up transformer t1 having its primary winding connected to a suitable source of alternating current such as indicated schematically at 40 a high potential for example 2500 volts will typically appear across the secondary winding.