Abstract: A programmable electronic time delay initiator includes a digital time-delay circuit that counts in response to a dual-resonator clock and, at the end of the programmed time delay, gates the pre-stored charge on a capacitor to a semiconductor bridge initiator to fire an explosive. The timer circuit includes a combined crystal/RC oscillator that provides high accuracy oscillations from the crystal or oscillations from the RC components in the event the crystal fails. The timer circuit functions in response to multi-part serial commands delivered on a conventional two-wire path. The timer is initially powered-on to provide power to a capacitor that supplies power to the time-delay and related circuits. An initial ATTENTION pulse initializes the circuitry and starts a watchdog timer that counts a fixed number of clock cycles and resets the logic if a following WRITE, ARM, or FIRE command is not received.

Abstract: An integrated field-effect initiator useful for the pyrotechnic initiation or detonation of explosives includes a semiconductor channel of a first conductivity type bounded on opposite ends by semiconductor material of an opposite conductivity type to define two PN junctions in the conduction path. The semiconductor channel is doped to define a conduction path of sufficiently high impedance to prevent unintended initiation. A gate electrode is positioned adjacent the channel and separated therefrom by an insulation layer to affect the conductivity of the channel as a function of a potential applied to the gate. In normal operation, an initiation electrical potential is applied to the opposite ends of the conduction path and a gate potential is applied to the gate to effect field-enhanced conduction in the path sufficient to allow vaporization of the path to cause initiation of an explosive material in contact with the path.

Abstract: An igniter which is triggered by a thermocouple for detonating an explosive material for forming an opening in a rocket motor case to render it non-propulsive in the event of a fire dangerously close thereto or for any other suitable purpose. The bridge therefor is preferably a suitable semiconductor bridge for handling a reduced amount of electrical energy which may be provided by the thermocouple. The thermocouple may be a plurality of pairs of dissimilar metal layers or foils alloyed together and the pairs connected in series.