Abstract: In a semiconductor device, impurity density at a base region of a protection transistor (9) is lower than impurity density at base regions of transistors (1, 2) which constitute a Darlington transistor (100). With high voltage impressed on a first output terminal (6), the protection transistor (9) first turns on because the impurity density at its base region is the lowest. Current thus allowed into the protection transistor (9) is amplified at the Darlington transistor (100) so that current equivalent to the amplified current is pulled out from current flowing in the output terminal (6). As a result, the first output terminal (6) is freed from high voltage impressed thereupon. The protection transistor (9) is obtainable in a process for forming the transistors (1, 2) by only lowering impurity density of the protection transistor (9) at the base region, thus omitting a special step for forming the protection transistor (9). Hence, cost for fabricating the semiconductor device is reduced.

Abstract: A package tester includes an inlet station for arranging a test board in which package sockets mounting packages are disposed in one or plural lines for performing package test by flowing an electric current through the package and transmitting signals to the package, the package being composed of parts including electric parts or electronic parts and being sequentially formed on a package tape, an inlet pusher for pushing the test board mounting the packages by a width of the test board in a feeding direction of the test board from the inlet station to the package socket, a conveyor for receiving the test board sequentially pushed out of the inlet station by the inlet pusher and conveying the received test board to a testing area, a contact device opposed to the conveyor and capable of being electrically connected to the test board arranged on the conveyor, an outlet station receiving the test board sequentially pushed out of the conveyor by sequentially pushing-out of the test board by means of the inlet pu