The base region is lightly doped and very thin so that it has a very limited number of holes. The heavily doped n-type emitter region is teeming with conduction-band (free ) electrons that easily diffuse through BE junction into the p-type base region where they become minority carriers. The forward bias from base to emitter narrow the BE depletion region, and the reverse bias from base to collector widens the BC depletion region. The figure shown the proper bias arrangement for both npn and pnp transistor for active operation as an amplifier. To operate the transistor properly, the two pn junction must be correctly biased with external dc voltages. The base region is lightly doped and very thin compared to the heavily doped emitter and the moderately doped collector region The pn junction joining the base region and the emitter region is called the base-emiter junction The pn junction joining the base region and the collector region is call base-collector junction The BJT have 2 types: Two n region separate by a p region – called npn Two p region separated by a n region – called pnp The three region are called emitter (E),base (B) and collector (C)
The BJT is constructed with three doped semiconductor regions separated by two pn junctions. If some data source only has data for the active region, this is probably good enough.Chapter 4 Bipolar Junction Transistors (BJTs)Ģ Objectives Describe the basic structure of the bipolar junction transistor (BJT) Explain and analyze basic transistor bias and operation Discuss the parameters and characteristics of a transistor and how they apply to transistor circuits In other words, all of the non-linearities are important, and the behaviour in regions outside of as well as including the active region are also important. I am interested in writing some simulations involving BJTs which requires more information than can be obtained from the typical transistor equations. Some might become dependent on each other if a complete circuit is drawn including an impedance on the base and collector (or emitter) nodes.Īre there any example devices which have (presumably large) tables of data available for download for measurements of these parameters? I don't know if these are all independent - I believe they all are. Transistor temperature, which other variables such as the Collector-Emitter current, might have a second order effect from.Transistor HFE (beta) which is a function of temperature.
To explain further, for a simple BJT circuit we have the following variables. Is there anywhere I can download some current-voltage data for a bipolar junction transistor? (It doesn't matter that much which one.)
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