| 摘要 |
When checking an item under test, for example a printed-circuit board having electrical modules, if it has been found that there is a defect present on the printed-circuit board, then the location of the fault on the item under test must be determined. To this end, the electrical state of electrical leads on the item under test (10) is determined with the aid of a sampling probe (14). The sampling probe (14) makes electrical contact both with the electrical lead to be checked and with an earth lead (22) on the item under test (10). The electrical signal picked off the electrical lead which is to be checked and the earth potential are transmitted via a coaxial cable (24) to an evaluation circuit (26). To this end, an electrical connecting lead (32) is provided on a printed-circuit board (28), via which the electrical signal is passed to the evaluation circuit (26). The electrical connecting lead (32) is passed between two earth leads (34) on the printed-circuit board, which earth leads are connected to the earth lead of the coaxial cable (24). The earth leads (34) are connected to an earth lead of the evaluation circuit (26). Using an arrangement constructed in this manner, it is possible to transmit radio-frequency electrical signals from the item under test to the evaluation circuit (26), and at the same time potential differences on the earth leads of the item under test and of the evaluation circuit are prevented. <IMAGE>
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