Multiple probe for testing electronic circuits - has pneumatically-operated rotating plunger for improved electric contact with reduced pressure

摘要

The multiple probe for testing electronic circuits comprises a pneumatically-operated array of circuit probes (1) mounted above the assembly under test (4). The lower face of the probe matrix (7) carries a printed circuit connector strip (6) by which the individual test prods (2) are connected to the test equipment through flexible leads (5) (8). Each probe has a bevelled tip which is connected to a spring loaded plunger operating within a pneumatic cylinder (9). The cylinder has at its lower end a spiral slot (12) with which a guide pin (11) fixed to the plunger engages. Application of pneumatic pressure to the plunger after it has been placed in contact with the respective test point (3) on the circuit under test, causes the point to be rotated slightly due to the action of the spiral slot and pin. This movement breaks down any surface film or oxydisation layer, thus enhancing the electrical contact.