Abstract: Electrical circuit continuity test apparatus for the high energy discharge circuitry of a firing unit couples to the stripline transmission line of the discharge circuitry but adds minimal inductance to the circuit. This is achieved by a coupling transformer having a core of high magnetic permeability alloy which loops around one of the strip conductors of the stripline. The primary winding, which couples into test circuit is merely another conductor wrapped around this core. The primary winding senses the reflected capacitive impedance of the discharge circuitry which includes an added capacitor to bypass the high energy switch of the discharge circuitry.Impedance sensing is accomplished by a resistance bridge driven by an oscillator and where imbalances indicating a defective circuit are sensed by a synchronous demodulator and a window comparator.