The flying probe test is a standard method used to test circuit boards for defectiveness, using probes that are able to move and access various test points on the board. A circuit board consists of many electrical circuits, each of which has inputs and outputs. During a test, a probe is first placed on the input test point of a circuit, as it provides a voltage or current source to that circuit. Another probe is used to measure the corresponding output, monitoring whether or not the board produces expected values.