BIPOLAR TRANSISTOR CHARACTERISTICS

Figure 7. Common-emitter characteristics of the Alo.48 n0.52As/GaQ Ing 53AS heterojunction bipolar transistor with (a) abrupt emitter and (b) graded emitter at 300 K. (Adapted from Ref. 32.)...

Makimoto, T., Yamauchi, Y. and Kimiakura, K. (2004) High-power characteristics of GaN/InGaN double heterojunction bipolar transistors . Applied Physics Letters, 84(11), 1964-1966. 

A digital signal processor (DSP) is used to monitor the input and output parameters of the APLC. The DSP then makes any needed adjustment in the amount of voltage compensation and current injection by modifying the switching characteristics of the insulated-gate bipolar transistors (IGBTs) in the APLC. 

The transient (dynamic) characteristics of a MOSFET are determined by capacitors and by the behavior of carriers in the device. In general, the capacitance is larger than that of a bipolar transistor. Table 4.9 shows the capacitances taken from the data sheet of 2SK2844 MOSFET. 

The first work that utilized a bipolar transistor was that of Prins (52). Using a natural p-type diamond bulk crystal as a substrate, carbon ions are ion implanted to form n-type-like regions with 3.2-pm-diameter wire as a implant mask. The energy level and mechanism of the carbon implantation cannot be estimated however, bipolar transistor behavior was achieved. The I-V characteristics are shown in Fig. 9. Although the current gain of ftp = Ic/h is only 0.11, the impact on researchers in this field was not insignificant. This was followed by several research activities, such as work on npn bipolar transistors with As implanted n-type-like regions and a point contact bipolar-like transistor (53). 

This is the characteristic family of curves for a 2N3904 NPN bipolar junction transistor. 

Figure 1 shows the symbols of common elements used in electronic circuits. These can be classed as either passive components, such as resistors, capacitors, inductors, and diodes, or active components, such as bipolar and field-effect transistors, and silicon-controlled rectifiers (SCRs). Some of the key features and physical characteristics of these devices are summarized in the first two sections of this chapter. 

Reference 2 also describes the on-off characteristics of the power semiconductors used in the bridges e.g. diodes, thyristors, triads, gate turn-off thyristors and bipolar power transistors. Only the steady state operations of bridges are described herein. For such operations it is assumed that the load is well matched to the rating of the bridge. The remainder of this section is an introduction to the subject of harmonic voltages and currents that are caused by variable speed systems for DC and AC motors. It emphasises the main aspects that affect the supply power systems. 

---