For the complete manual, Click Here TOS5101 is designed exclusively to withstand voltage testing of electronic equipment and components conforming to various safety standards. The use of a high-luminance, large fluorescent display tube for the display enables data including measured values, status, and judgment results to be extremely legible. The PASS/FAIL function employs a window comparator method that enables TOS5101 to make a failed judgment of current leakage over the upper reference value and below the lower reference value which can be set on the front panel.