barcode reader vb.net codeproject TRANSISTOR AMPLIFIERS in Software

Print Quick Response Code in Software TRANSISTOR AMPLIFIERS

TRANSISTOR AMPLIFIERS
Reading QR Code JIS X 0510 In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Denso QR Bar Code Generator In None
Using Barcode encoder for Software Control to generate, create QR Code image in Software applications.
The design of a practical transistor ampli er is a more complex process than what has been described in the preceding sections A number of issues must be addressed in order to produce a useful ampli er design; such a detailed discussion is beyond the scope of this book, primarily because the intended audience of this text is not likely to be involved in the design of advanced ampli er circuits However, it is important to brie y mention two topics: frequency response limitations of transistor ampli ers; and the need for multistage ampli ers consisting of several transistor ampli er stages that is, several individual ampli ers like the ones described in the preceding sections Other issues that will not be addressed in greater detail in this book include: ampli er input and output impedance; impedance matching between ampli er stages, and between source, ampli er and load; direct-coupled and transformer-coupled ampli ers; differential ampli ers; and feedback However, some of these issues will be indirectly addressed in 12, devoted to operational ampli ers, where it will be shown that for many instrumentation and signal-conditioning needs, a non electrical engineer can be satis ed with the use of integrated circuit ampli ers, consisting of multistage transistor ampli ers completely assembled into an integrated circuit chip Frequency Response of Small-Signal Ampli ers When the idea of a coupling capacitor was introduced earlier in this chapter, the observation was made that the input and output coupling capacitors (see Figure 107, for example) acted very nearly like a short circuit at AC frequencies In fact, the presence of a series capacitor in the AC small-signal equivalent input circuit has very much the effect of a high-pass lter Consider the small-signal equivalent circuit of Figure 1035, which corresponds to a BJT common-emitter ampli er In this circuit, a single coupling capacitor has been placed at the input, for simplicity Let us compute the frequency response of the small-signal equivalent circuit of Figure 1034 If we assume that RB RS and RB hie , then we can approximate the base current by iB = and vin = hie hie + RS + 1 j CB vS (1056) vin hie (1055)
QR Code Decoder In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
Print Quick Response Code In Visual C#.NET
Using Barcode creator for .NET Control to generate, create QR Code 2d barcode image in Visual Studio .NET applications.
Part II
Generate QR Code In .NET
Using Barcode generator for ASP.NET Control to generate, create QR Code image in ASP.NET applications.
QR Code Creator In Visual Studio .NET
Using Barcode encoder for .NET Control to generate, create QR Code JIS X 0510 image in .NET applications.
Electronics
Encoding QR-Code In Visual Basic .NET
Using Barcode generation for .NET Control to generate, create QR Code image in VS .NET applications.
Encoding Code 3/9 In None
Using Barcode maker for Software Control to generate, create Code 39 Extended image in Software applications.
CB +
Bar Code Encoder In None
Using Barcode drawer for Software Control to generate, create barcode image in Software applications.
Code 128 Code Set B Printer In None
Using Barcode generator for Software Control to generate, create Code 128B image in Software applications.
iout +
Painting UPC Code In None
Using Barcode maker for Software Control to generate, create UPC A image in Software applications.
Barcode Encoder In None
Using Barcode drawer for Software Control to generate, create barcode image in Software applications.
vS + _
Planet Generation In None
Using Barcode generator for Software Control to generate, create USPS Confirm Service Barcode image in Software applications.
Generate Barcode In VS .NET
Using Barcode generation for Reporting Service Control to generate, create barcode image in Reporting Service applications.
vin _
UPC A Creator In Visual Basic .NET
Using Barcode creator for .NET framework Control to generate, create UPC Symbol image in Visual Studio .NET applications.
EAN 128 Generator In None
Using Barcode creation for Microsoft Excel Control to generate, create GS1-128 image in Microsoft Excel applications.
hie hfe IB
Draw Matrix Barcode In .NET Framework
Using Barcode generation for VS .NET Control to generate, create Matrix 2D Barcode image in .NET framework applications.
ECC200 Drawer In C#.NET
Using Barcode creation for .NET framework Control to generate, create Data Matrix image in Visual Studio .NET applications.
vout _
DataMatrix Creation In .NET
Using Barcode encoder for ASP.NET Control to generate, create Data Matrix image in ASP.NET applications.
2D Barcode Encoder In .NET
Using Barcode encoder for ASP.NET Control to generate, create Matrix Barcode image in ASP.NET applications.
Figure 1035 Small-signal equivalent circuit
so that the output voltage is given by vout = RC or vout = RC vS RL hf e hie + RS + 1 j CB (1058) RL hf e iB = RC RL vin hie (1057)
This expression for vout is clearly a function of frequency, approaching a constant as tends to in nity Note that, in effect, the cutoff frequency is determined at the input circuit by the effective RC combination of equation 1059: B = 1 (RS + hie )CB (1059)
Clearly, if we wished to design an audio ampli er (that is, an ampli er that can provide an undistorted frequency response over the range of frequencies audible to the human ear), we would select a coupling capacitor such that the lower cutoff frequency in the circuit of Figure 1035 would be greater than 2 20 rad/s A similar effect can be attributed to the output coupling capacitor, CC , in Figure 107, and to the emitter bypass capacitor, CE , resulting in the cutoff frequencies C = and E = 1 ro C E (1061)
Vout ( j ) VS
1 (RC + RL )CC
(1060)
where ro is the output impedance of the ampli er The highest of the three frequencies given in equations 1059 through 1061 is often E , and this is therefore the lower cutoff frequency of the ampli er Figure 1036 illustrates the general effect of a nonideal coupling capacitor on the frequency response of the common-emitter ampli er The frequency response of a bipolar transistor ampli er is generally limited at the high-frequency end by the so-called parasitic capacitance present between pairs of terminals at the transistor (don t forget that any two conductors separated by a dielectric air, for example form a capacitor) Figure 1037 depicts a highfrequency small-signal model (called the hybrid-pi model) of the BJT, which includes the effect of two capacitances, CBE and CCB These two capacitances can be safely ignored (by treating them as open circuits) at low and mid frequencies
Copyright © OnBarcode.com . All rights reserved.