Transistor Circuit Configurations (CB, CE, CC): As already mentioned, a Transistor Circuit Configurations is a three-terminal device (having three terminals namely emitter, base and collector) but we require four terminals—two for the input and two for the output for connecting it in a circuit. Hence one of the terminals of the transistor is made common …
Ebers Moll Model for PNP Transistor: Device modelling aims at relating physical device parameters to device terminal characteristics. Device modelling is especially important for integrated circuits, since simple and accurate device models are required to predict the performance of a circuit. Generally, by making a model more accurate, we make it more complex. Thus, there …
Base Spreading Resistance: With two depletion layers penetrating the base, the base holes are confined to the thin region of P-type semiconductor illustrated in Fig. 10.12. The resistance of this thin region (or section) is called the base spreading resistance rbb′. With the increase in reverse bias VCB on the collector diode, the width of the P-section …
Current Amplification Factor: There are two current amplification factors, the alpha factor (α) and the beta factor (β) defined below : The alpha factor (α) is also called the current amplification factor and is the ratio of change in collector current (IC) to change in emitter current (IE). In general, The beta factor (β) is …
Explain Transistor Current Components: The various transistor current components which flow across the forward-biased emitter junction and reverse biased collector junction are indicated in Fig. 10.11. The current flowing into the emitter is referred to as the emitter current and designated as IE. The emitter current IE consists of two constituents (hole current IhE due …
Important Points Regarding Working of Transistors: The noteworthy points regarding working of transistors are summarized below. 1. Current conduction in N-P-N transistor is by electrons and the conventional current flow will be in the opposite direction. Current conduction in P-N-P transistor is by holes but in external leads, the current conduction will be by flow …
Important Points Regarding Working of Transistors Read More »
What is Transistor Biasing? – Types of Biasing As already mentioned, for normal operation of a transistor emitter-base junction is always forward biased and collector-base junction is always reverse biased. For a moment if the Transistor Biasing of emitter-base junction is ignored and only collector-base junction, which is reverse biased [Fig. 10.6 (a)] is considered, …
Transistor Action : Operation of PNP Transistor: Transistor action – Transistors of both types (P-N-P and N-P-N) behave exactly in the same way except change in biasing and majority carriers. In P-N-P transistors the conduction is by holes whereas in N-P-N transistors conduction is by electrons. However, N-P-N transistors are preferred due to their better …
Transistor Terminals (Emitter, Collector and Base): As mentioned already, transistor is a single crystal in which there are two P-N junctions, as shown in Fig. 10.1. The idea behind is to have first section to supply the charges (either holes or electrons) to be collected by the third section through the middle section. One side …
Transistor Terminals (Emitter, Collector and Base) Read More »
Transistor Construction: The transistor construction consists of a silicon or germanium (preferably silicon because of its smaller cutoff current ICBO, smaller variations in ICBO due to variations in temperature and higher operating temperature) crystal in which a layer of N-type material is sandwiched between two layers of P-type material, as shown in Fig. 10.1 (a). Alternatively …