Abstract: Prefires in a high-power, high-frequency, multi-stage pulse generator are detected by a system having an EMI shielded pulse timing transmitter associated with and tailored to each stage of the pulse generator. Each pulse timing transmitter upon detection of a pulse triggers a laser diode to send an optical signal through a high frequency fiber optic cable to a pulse timing receiver which converts the optical signal to an electrical pulse. The electrical pulses from all pulse timing receivers are fed through an OR circuit to start a time interval measuring device and each electrical pulse is used to stop an individual channel in the measuring device thereby recording the firing sequence of the multi-stage pulse generator.

Abstract: A portable ohmmeter for use in measuring the resistance of an electrical contact including a direct current battery, and a resistive element serially connected with the contact and the battery to form a complete circuit. Included are means for sensing the voltage drop across both the resistive element and the contact, and a digital ratiometer for displaying the value of the resistance of the electrical contact. The digital ratiometer displays the ratio of the voltage drop across the contact to the voltage drop across the resistive element, which ratio is also the value of the resistance of the contact. Also included are means for calibrating the ratiometer as a function of the resistance of the resistive element.