Figure true confessions magazine 1 The image above is an example of biased base. A voltage source V

Figure true confessions magazine 1 The image above is an example of biased base. A voltage source VBB forward true confessions magazine biased diode emitters through a current limiting resistor RB. Kirchoff's voltage law states is the voltage at RB VBB - VBE. Ohms Law gives the base current equation .......... 1
Where VBE = 0.7 V for a silicon transistor (0.3 V for germanium). In the Load line dc collector circuit, reverse bias voltage source true confessions magazine VCC through a diode RC collector. By Kirchoff's voltage law, VCE = VCC - IC.RC equation ..................... 2 In a given circuit, VCC and RC are constant, VCE and IC are variable. We can rearrange equation 2 to get: Equation 3 As evidenced true confessions magazine in basic mathematics, graphs of linear equations always a straight line with a slope m and the intersection of the vertical b. Figure 2 Figure 2 shows the graph of the equation 3 cut the curve - the curve of the collector. The intersection of the vertical is at VCC / RC. The intersection of the horizontal is at VCC, and the slope is -1/RC. This line is called true confessions magazine the dc load line because this line expressed all possible operating point. The intersection of the load line with the base current is the dc operating point than the transistor. Example question 1 2N3904 transistors in Figure 3 Figure 3 is a silicon transistor with Βdc of 100. How much is the price that will be read by a dc voltmeter to the terminals collector - emitter? Answer: At first - first get the base current. The flow is equal to the voltage drop across the resistor. Base divided by resistance:
Collector current true confessions magazine is IC = IB = βdc x 100 x 9.3 mA = 0.93 mA Voltage collector - emitter equal to the collector supply voltage minus the voltage drop across the collector resistor: VCE = VCC - (IC x RC) = 20 - ( 0.93 (0.001) 5 (1000)) = 15.4 V Figure 3 shows the same circuit in the system of land negative (negative - ground system). For simplicity we only show the voltage supply +10 V and +20 V. If you look at a simplified scheme as figure 4, remember that this time means the terminal - the negative terminal of the power supply is grounded to get the complete path for the current. Figure 4 Example question 2 2N4401 true confessions magazine transistors in Figure 5 is a silicon transistor true confessions magazine with βdc of 80. Draw the dc load line. Where is the point Q if RB = 390 kΩ Figure 5 Answers
Collector true confessions magazine current is IC = IB = βdc x 80 x 75.1 mA = 6 mA VCE = VCC - IC RC = x 30-6 (0.001) 1.5 (1000) = 21 V Figure 6 shows the point Q. The coordinates are IC = 6 mA and VCE = 21 V. Note that the point Q is located on the dc load line for load line stating all possible operating point. If we want to change the price of the RB point Q will be shifted to another point on the load line. Example question 3 transistors in figure 7 has βdc of 80 and VCE (sat) = 0.1 V RB set to achieve saturation of the transistor. What is the cost of the IC (sat)? RB price is concerned? Figure 7 Answers If we reduce the RB, the base current increases, the collector current increases, and the voltage drop across true confessions magazine RC increases; This reduces the voltage of the collector - emitter. Finally, VCE is reduced to 0.1 V. At this point, the diode reverse biased collector precise loss, prevent further additions of collector current. Saturated transistor and the collector current is
In low power transistor, VCE (sat) only a few tenths of volts, small enough to be ignored. true confessions magazine As many people true confessions magazine approach the collector terminal imagine - emitter shorted, equivalent true confessions magazine to VCE = 0. If the transistor true confessions magazine in Figure 7 saturated, therefore, is ideally collector true confessions magazine shorted to ground. Collector current flowing through the resistor 220 Ω down disappear into the collector, similar to the water disappears down through the exhaust duct. This is called a transistor with grounded emitter current release (current sink); collector current to flow downward through the soil into the current release. Example 4 Figure about dc load line in figure 8 for RC = 20 kΩ Figure 8 Answer If the transistor operates in the saturation region, a grounded collector is ideal. In this case, all the voltage appears across the resistor true confessions magazine and the collector
Because of that, the saturated state, true confessions magazine the transistor release 1 mA to the ground. If the transistor is working in the area of plug point (cutoff) true confessions magazine collector terminal - its emitter was open, therefore, all the supply voltage appears at the open terminal, and VCE (cutoff) = 20 V Figure 9 Figure 9 shows the dc load line (which is down ). Example question 5 Capacitive reactance is inversely proportional to the frequency. Because of this, the capacitor has an infinite reactance to zero frequency, equivalent to an open state to dc. What is the voltage of the collector - emitter true confessions magazine in picture 10? Use of beta dc of 100 for transistor 2N3904 true confessions magazine and by 80 to