Continuously variable electronic load tester for use with nuclear instrumentation system high voltage power supplies

A method of operating a continuously variable electronic load tester circuit, the method comprising:

• receiving, by a variable electronic load circuit, a voltage from a power supply;
• presenting, by the variable electronic load circuit, a load to the power supply;
• operating, by a control circuit, a plurality of transistors connected in series as variable resistors;
• controlling, by the control circuit, a resistance of the variable resistors to control the load presented to the power supply;
• comparing, by an error amplifier, a first voltage to a feedback signal;
• and
• outputting, by the error amplifier, an output signal indicative of a difference between the first voltage and the feedback signal, wherein the output signal is to control the resistance of the variable electronic load circuit to vary the load presented to the power supply, wherein the feedback signal is proportional to a current flowing through the variable electronic load circuit.

A variable electronic load tester circuit, comprising:

• a control circuit;
• and
• a variable electronic load circuit coupled to the control circuit to receive a voltage from a power supply and present a load to the power supply, wherein the variable electronic load circuit comprises:
• a plurality of transistors connected in series and operable as variable resistors;
• and
• wherein the control circuit is to control a resistance of the variable resistors to control the load presented to the power supply;
• and
• wherein the control circuit to compare a first voltage to a feedback signal and an output signal indicative of a difference between the first voltage and the feedback signal, wherein the output signal is to control the resistance of the variable electronic load circuit to vary the load presented to the power supply, wherein the feedback signal is proportional to a current flowing through the variable electronic load circuit.