Electric discharge apparatus

Abstract

The invention relates to a gas discharge tube (30) of a type that may be used for example in gas turbine engine (10) ignition systems. The gas discharge tube (30) has an envelope (42) containing a gas therein and the envelope has a pair of spaced electrodes (38, 40) for application of an electric potential difference across the gas. An electromagnetic radiation source (44), such as a deep UV light source, is arranged to emit photons (50) into the envelope (42) so as to initiate ionisation of the gas, thereby reducing the potential difference required to cause electrical conductance between the electrodes. The electromagnetic radiation source, which may comprise light emitting diodes, may be selectively controlled.

Dependencies are inferred from the claim text.