| 摘要 |
A system for testing conductor lines in a printed circuit board includes circuitry for the burning out of constricted regions of the printed circuit lines so as to insure that such defects are noticed. The system includes circuitry for measuring the resistance in a path through a printed circuit line under test and including connecting circuitry to a generator of an electrical pulse. A resistor network and switching circuitry is employed for adjusting the resistance of the path through a desired value. The electrical pulse is generated by the discharge of a capacitor previously charged to a predetermined value of voltage, the discharge occurring via a pulsing circuit switch which limits the duration of the pulse through a predetermined value of sufficiently short duration to prevent damage to the circuit board associated with excessive heating. Monitoring circuitry including a peak detector and comparators is employed for sensing a sudden change in test current amplitude, as well as test currents having amplitudes of an acceptable range, for terminating the test current pulse prematurely upon an indication of burnout, thereby to protect the circuit board.
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