IN-CIRCUIT TESTER

• Main Author: NAGANO KATSUMI
• Format: Patent
• Language: English
• Published: 06.06.1989
• Subjects: MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; TESTING

PURPOSE:To measure a small capacity with a high accuracy by contacting means to first and second terminals to which capacities are not connected and to third and fourth terminals to which measured capacities are connected, respectively, and measuring the output signals of respective contacting means. CONSTITUTION:To a printed wiring substrate, pattern lands PL1 and PL2 to which condensers are not connected, and pattern lands PL3 and PL4 to which both terminal parts of a condenser C is soldered, are provided, and to them, test lands TL1-TL4 are successively provided, respectively. All of them are made into the same shape. Probe pins CP1-CP4 as contacting means are mounted to a substrate PLT. Relay switches RL1, RL2, RL3 and RL4 are turned on by a control part CT, and a floating capacity Cp from a measurement system up to the test lands TL1 and TL2 is obtained from the output voltage of an arithmetic amplifier MOA for a measurement. Next, switches RL3-RL6 are turned on, the capacity Cp is subtracted from a capacity obtained from the output voltage of the amplifier MOA, and thereby, the real capacity of the condenser C can be obtained.