AUTOMATIC VARIABLE PERIOD TYPE FUNCTION FINE CURRENT MEASUREMENT SYSTEM

PURPOSE:To take a measurement efficiently and to improve ability in measurement by deciding the current of an element to be measured when the value becomes a decision level and ending a test pattern during execution at present forcibly. CONSTITUTION:When a test pattern is applied from a test pattern generating part 12 to the element 11 to be measured through a driver 13, a current flowing to a termi nal VSS of the element 1 is converted by a comparator 22 and a resistance 23 into a corresponding voltage value, which is compared 24 with the decision level of a power source 24, so that the comparison output is sent to a decision display circuit 20 and an AND gate 21. Further, the propriety of the high-low level of the output signal of the element 11 is decided by comparators 151 and 152 on the basis of the expected value pattern signal SP of the generating part 12 and when the level does not reaches a specific value, that is displayed on a circuit 20. On the other hand, when the output of the element 11 is a specific value and a specific time is already elapsed after the output of the comparator 24 exceeds the decision level, that is detected by a gate 21 and the generating part 12 is forced to finish the current test pattern under execution and move to the next pattern.