Abstract: An apparatus for testing the operativeness of a squib in an active restraint system wherein the squib has a resistance value, when operative, within a predetermined range of resistance values. The squib is connected in series with a firing circuit to a first source of electrical energy. A monitoring circuit includes a second source of electrical energy and a bridge circuit. The bridge circuit includes a biasing resistor network and a reference resistor network, both networks being operatively connected to the second source of electrical energy. The biasing resistor network establishes a flow of test current through the squib, the test current being the only continuous non-actuating current through the squib. The biasing resistor network establishes a test voltage value at one terminal of the squib. The monitoring circuit further includes a comparator for comparing the test voltage value at the one terminal of the squib against the squib reference voltage value of the reference resistor network.