A direct current (DC)-DC converter (100;412,414,416,418,420), comprising: a transformer comprising a primary winding and a secondary winding ; and a gas tube-switched inverter circuit (108;500) comprising: a first inverter load terminal and a second inverter load terminal , each of said first inverter load terminal and said second inverter load terminal coupled to said primary winding; a first inverter input terminal and a second inverter input terminal , each of said first inverter input terminal and said second inverter input terminal couplable to a first DC node (200;300;402,404,406,408,410); and a first plurality of gas tube switches (120,122,124,126;502,504,506,508) respectively coupled between said first and second inverter load terminals and said first and second inverter input terminals, said first plurality of gas tube switches configured to operate to generate an alternating current (AC) voltage at said primary winding; wherein each of said first plurality of gas tube switches (120,122,124,126;502,504,506,508) includes an anode and a cathode located within a chamber , characterised in that the anode and the cathode are separated by a discharge gap and wherein the chamber further contains an ionizable gas that occupies the discharge gap. a transformer comprising a primary winding and a secondary winding ; and a gas tube-switched inverter circuit (108;500) comprising: a first inverter load terminal and a second inverter load terminal , each of said first inverter load terminal and said second inverter load terminal coupled to said primary winding; a first inverter input terminal and a second inverter input terminal , each of said first inverter input terminal and said second inverter input terminal couplable to a first DC node (200;300;402,404,406,408,410); and a first plurality of gas tube switches (120,122,124,126;502,504,506,508) respectively coupled between said first and second inverter load terminals and said first and second inverter input terminals, said first plurality of gas tube switches configured to operate to generate an alternating current (AC) voltage at said primary winding; wherein each of said first plurality of gas tube switches (120,122,124,126;502,504,506,508) includes an anode and a cathode located within a chamber , characterised in that the anode and the cathode are separated by a discharge gap and a first inverter load terminal and a second inverter load terminal , each of said first inverter load terminal and said second inverter load terminal coupled to said primary winding; a first inverter input terminal and a second inverter input terminal , each of said first inverter input terminal and said second inverter input terminal couplable to a first DC node (200;300;402,404,406,408,410); and a first plurality of gas tube switches (120,122,124,126;502,504,506,508) respectively coupled between said first and second inverter load terminals and said first and second inverter input terminals, said first plurality of gas tube switches configured to operate to generate an alternating current (AC) voltage at said primary winding; wherein each of said first plurality of gas tube switches (120,122,124,126;502,504,506,508) includes an anode and a cathode located within a chamber , characterised in that the anode and the cathode are separated by a discharge gap and wherein the chamber further contains an ionizable gas that occupies the discharge gap. <EOS>