Bipolar Transistor Tester / Digital IC Tester for Physics Lab
  A very simple low cost bipolar transistor tester for physics lab is given. The proposed circuit not only indicates the type of transistor(NPN/PNP) but also indicates the terminals(emitter, base and collector) using simple dual color (red/green) LEDs. Color diagrams of testing procedure have been given for easy following. This article describes the construction of this apparatus in all detail with schematic circuit diagram, circuit layout and constructional illustration. The second part describes a simple circuit to test digital ICs in a physics lab. Small scale integration digital ICs like logic gates, flip-flops, registers, counters, decoders, multiplexers etc are used in physics lab for various purposes either in a commercially obtained equipment or lab made circuits. The non-functionality of a circuit may call for a test of the digital chip. Commercially available test equipment is expensive, bulky and some times useless with regard to the concerned test. This article describes an inexpensive, portable and useful digital IC test circuit that could be helpful in detecting the actual fault with the chip provided the data sheet for the chip is available. In a very convenient and easy way. The article contains neat diagrams and illustrations to help the reader build a proper functional digital IC tester. 
Raju Baddi
physics.pop-ph physics.ed-ph