EXPLODING BRIDGEWIRE TESTER WITH SQUARE WAVE GENERATOR

• US 3,689,830 A
• Filed: 04/05/1971
• Issued: 09/05/1972
• Est. Priority Date: 04/05/1971
• Status: Expired due to Term

• Current Assignee: James M. Caldwell, Thomas J. Keating, William R. Day
• Original Assignee: James M. Caldwell, Thomas J. Keating, William R. Day
• Inventors: James, M. Caldwell, William, R. Day, Thomas, J. Keating
• Primary Examiner(s): Gerard R. Strecker
• Application Number:
  US05/131,312
• Time in Patent Office: 519 Days
• Field of Search: 324/51,54,66,73,133
• US Class Current: 324/502
• CPC Class Codes: F42B 35/00 Testing or checking of ammunition apparatus for measuring the energy of projectiles G01L5/14
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58

Abstract

The capacitance of an exploding bridgewire (EBW) with a series spark gap is used as a measure of its acceptability. A square wave is applied to the EBW through a resistor. The resistor and EBW capacitance form an integrator for the square wave. A logic system having inputs connected both to the square wave and to the integrated square wave gives outputs indicative of whether the EBW has low capacitance (open bridgewire), normal capacitance (acceptable), or high capacitance (shorted gap).

Claims

1. A tester for an electro-explosive device wherein said device includes the series connection of a spark gap and an exploding bridgewire, including:

a resistor, a square wave generator having an output connected through said resistor to said device;

logic means having inputs connected to said square wave generator, and having outputs connected to indicators;

a Schmitt trigger voltage level sensing means having an input and an output;

said logic means having other inputs connected to said output of said level sensing means, and;

said input of said level sensing means connected to the connection of said resistor to said device;

wherein said logic means includes first, second, and third oneshot multivibrators each having a trigger input and an output, and AND gate, and first and second inhibit gates, each of gates having inputs and an output, said inhibit gates each having an inhibit input;

wherein said first and third multivibrators have their trigger inputs connected to said output of said square wave generator, with the output of said first multivibrator connected to an input of said AND gate and to the inhibit input of said first inhibit gate and the output of said third multivibrator connected to an input of each said second inhibit gate and said AND gate;

said trigger input of said second multivibrator connected to the output of said level sensing means, with the output of said second multivibrator connected to an input of said first inhibit gate;

said output of said output of said square wave generator being also connected to an input of each said AND gate and said second inhibit gate;

said output of said level sensing means being also connected to an input of said AND gate and to the inhibit input of said second inhibit gate; and

said indicators being three in number, with a respective indicator connected to a respective output of each of said gates.

2. A tester as set forth in claim 1 wherein said first and third multivibrators have different pulse width outputs.