Abstract: This invention provides an initiating device 10 for an electronic detonator, which includes two spaced electrical conductors 12 located on an insulating substrate 14; and two separate resistive means in the form of thick film resistive bridges 16 extending between the electrical conductors 12, for releasing energy upon application of an electrical current to the resistive bridges 16. An explosives or pyrotechnic composition, generally designated by reference numeral 18, covers the resistive bridges 16. It will be appreciated that should one of the bridges 16 fail, the other bridge 16 would still initiate the device 10. The size of the contact interface between the bridge 16 and the explosives composition 18 is also doubled, making the initiating device 10 even more reliable. As a result the initiating device 10 is suitable for a wide range of different applications.