Abstract: A contact head (6) for an electrical test device (1) for electrically testing substrates, which have electrical contact points, with at least two guide plates (13, 14) that are arranged to each other by a spacer (15) and each have guide openings (16) essentially aligned with each other for receiving pin-shaped contact elements (8) and are oriented to each other by a centering device (20), wherein the centering device (20) has four centering pins (19), which are displaceably mounted in a slot (23), extending toward a center (Z) of the contact head (6), at least of one of the guide plates (13, 14), and wherein the centering pins (19) are each held in a centering opening (18) of the spacer (15). It is provided that the centering openings (18) each have only one guide surface (21) oriented at least essentially parallel to a radial axis (R)—in relation to the center (Z).

Abstract: A contact head (6) for an electrical test device (1) for electrically testing substrates, which have electrical contact points, with at least two guide plates (13, 14) that are arranged to each other by a spacer (15) and each have guide openings (16) essentially aligned with each other for receiving pin-shaped contact elements (8) and are oriented to each other by a centering device (20), wherein the centering device (20) has four centering pins (19), which are displaceably mounted in a slot (23), extending toward a center (Z) of the contact head (6), at least of one of the guide plates (13, 14), and wherein the centering pins (19) are each held in a centering opening (18) of the spacer (15). It is provided that the centering openings (18) each have only one guide surface (21) oriented at least essentially parallel to a radial axis (R)—in relation to the center (Z).

Abstract: A testing device for electrically testing an electrical test specimen, in particular a wafer, the testing device having a test head in which at least one testing contact is mounted for electrically contacting a test specimen. At least one outlet opening for discharging a gas, in particular a protective gas, into a contact region, is provided in a wall of the test head.