  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.
