Partailly guarded switching matrix for automatic electronic test equipment

A system for capacitance testing of a unit under test (UUT), comprising:

• a plurality of test points, each test point associated with an input relay and an output relay, such that the number of test points is equivalent to the number of input relays and the number of output relays, wherein the plurality of test points are divided into at least two groups;
• a stimulus source configured to provide a stimulus signal;
• a first stimulus rail, the first stimulus rail electrically connected to each of the test points in the first group via the associated input relays, wherein the first stimulus rail is electrically connected to the stimulus source via a first group stimulus relay;
• a second stimulus rail, the first stimulus rail electrically connected to each of the test points in the second group via the associated input relays, wherein the first stimulus rail is electrically connected to the stimulus source via a second group stimulus relay;
• a first group guard relay electrically connected to each of the test points in a first group via the associated output relays;
• a second group guard relay electrically connected to each of the test points in a second group via the associated output relays;
• a guard rail, the guard rail coupled to the first group guard relay and the second group guard relay;
• a first group return relay electrically connected to each of the test points in a first group via the associated output relays;
• a second group return relay electrically connected to each of the test points in a second group via the associated output relays;
• a current measurement rail, the current measurement rail coupled to the first group return relay and the second group return relay;
• a current meter coupled to the current measurement rail;
• and
• a controller operably coupled to the stimulus source, the input relays, the output relays, the guard relays, the return relays, and the current meter.