Abstract: An exploding bridge wire detonator for use in high temperature downhole oil well tools is set forth. It is made of a high temperature stable secondary explosive which will be exposed to extremely high ambient temperatures such as 500.degree. F. This apparatus includes a housing supporting a pair of conductor wires which connect with a sacrificial exploding bridge foil or wire connected across the conductor wires. The sacrificial bridge is immediately adjacent to the explosive material in cylindrical form, and a reflector is included therein. The reflector preferably has high shock impedance to reflect shock waves traveling through the explosive from the exploding bridge. The reflector is transverse to the explosive mass but does not fully block off explosive shock wave propagation through the explosive material.

Abstract: In the preferred and illustrated embodiment of a DC to DC power converter in a sonde and exposed to high temperatures, a transformer with primary and secondary provides AC to a full wave rectifier bridge. The bridge output is DC with ripple on it. The bridge output is connected serially to the primary winding and also to a shunt capacitor. The circuit provides high temperature performance including slower switching speeds, reduced power dissipation and wider current range.

Abstract: For use in a perforating gun assembly, a perforating gun detonator is disclosed. One embodiment is hermetically sealed while the other has openings therein to admit well fluids. In both embodiments, a narrow conductive metal foil is provided with a current to vaporize the narrow foil, explode the foil and propel a flyer driven by a shock wave for detonation of a spaced secondary explosive. The explosive then couples explosion into a detonating cord against a shoulder in a housing adjacent to the secondary explosive. The current is formed by means of an AC voltage multiplier circuit providing a charge on a capacitor which is discharged through a spark gap. Charging circuitry includes a blocking capacitor to prevent DC and a resistor for bleeding a small current from the capacitor to ground which prevents static or stray current accumulation.