Patent ID: 8319503

Claim:
A test apparatus for measuring a characteristic of a device under test, said test apparatus comprising: (a) a guarded first signal path conductively connected to a signal source and conductively connected to a terminal of said device under test; and (b) an unguarded second signal path conductively connected to said signal source and conductively connected to said terminal of said device under test, said first signal path operative to conductively connect said signal source to said terminal without disconnecting portions of said second signal path from said signal source and said terminal and said second signal path operative to conductively connect said signal source to said terminal without disconnecting portions of said first signal path from said signal source and said terminal, wherein said second signal path includes a filter to exclude higher frequency components of a signal from said signal source, and further wherein said second signal path includes a plurality of resistors, each resistor of the plurality of resistors conductively interconnectable with said filter and said terminal by operation of a respective one of a plurality of switches.