Electronic in-circuit PCB testers & identifier PCB tester

Abstract

various types of electronic card test equipment are freely available today for different types of electronic printed circuit boards. A company certainly wants to pick the most suitable tester to suit their needs, and more importantly a tester that will fit into their bUdget. Today a company can easily import in-circuit testers that will cost well in the reglon of six figures. The cheaper the equipment go, the less features one can expect from the equipment. Like all other big decisions in life, this might also be a tough one for a company. Part one of this thesis will consider most of these questions, and will also give more insight on what type of specifications to look for. This section will also explain the different types of faults that occur, the repair costs involved, different types of card testers available and some of their features. Advanced in-circuit testing techniques will also be explained. Part two of this thesis describes the design and development of the Identif ier Card Tester. The" Program Control and Impulse Sender Card", (referred to as "Identifier Card") is one of the cards used in a system called "Electronic Identifier". The electronic identifier was developed to enable a subscriber directory number, a line or equipment numbers, or in general, the origin of information and classes-of-service to be determined by way of an existing connection within a telephone exchange. The system was designed for the purpose of incorporating it into the existing public exchanges where no identifier wires are available. It operates on the principle of a switching circuit (line) tester. The identification pulses are evaluated with the aid of 6 mm bistable magnetic ring cores according to the current steering principle. The program control and the output circuit uses a transistor, a magnetic core/transistor or a magnetic core/thyristor circuit. The electronic identifier is mostly used with "Routiners" in Electra-mechanical exchanges. The biggest percentage of failures on these systems are caused by the Identifier Card and hence the request for the development of a "Identifier Card Tester".