Monitor for repetitive pulse forming circuit

Claim 1

For monitoring the operation of a repetitive pulse forming network which is designed to supply a load circuit with short pulses of electric current at a frequency corresponding to the frequency of a train of periodic control signals, said network comprising a first capacitor, means for coupling said first capacitor in series circuit relationship with the load circuit to a d-c power supply from which said first capacitor accumulates a charge, controllable switching means which is turned on by said control signals to provide a low-resistance path for discharging said first capacitor, through the load circuit, and commutating means operative in delayed response to turn on of said switching means for turning off said switchinG means, whereupon said switching means remains off until the next control signal is received and said d-c power supply recharges said first capacitor, the improvement comprising: a. a second capacitor; b. means for connecting said second capacitor in parallel with said load circuit so that each time said switching means is turned on to discharge said first capacitor through said load circuit said second capacitor charges to a voltage having an appreciable magnitude and a predetermined polarity; c. a discharge circuit including a resistor in series with said second capacitor and having a relatively long time constant so that during the intervals when said switching means is off said second capacitor will slowly discharge, said discharge circuit requiring more time than the normal period between consecutive control signals to discharge fully said second capacitor; and d. means responsive to the continuing presence across said second capacitor of voltage of said predetermined polarity for indicating that the pulse forming network is functioning properly.