UNIVERSITY OF CALIFORNIA AT BERKELEYCollege of EngineeringDepartment of Electrical Engineering and Computer SciencesEE105 Lab ExperimentsPrelab 6: Biasing CircuitryName:Lab Section:R2+VOU T−R1VCCFigure 1: Resistive divider “voltage source”1. Consider the resistor networ k shown in Figure 1. Let VCC= 10 V, R1= 9.35 kΩ, and R2= 650 Ω. Wecan turn this resistive divider into a voltage source with an output resistance by taking its Th´eveninequivalent. Find the open circuit output voltage and the output resistance of this voltage source.2. Now, consider a BJT voltage source such as the one shown in Figure 2. Size resistor RCto achieve anoutput voltage of 65 0 mV. Let VCC= 10 V, IS= 26.03 fA, and VT= 26 mV. Ignore the Early voltagefor this calculation.3. Find the output impedance and the power dissipa ted by this BJT voltage source. Hint: Remember thedefinition of power, P = I V .12−VOU T+RCICVCCFigure 2: BJT voltage source4. If we were to resize the resistors of our resistive divider (Figure 1) to achieve the same output impedanceas the BJT voltage source given the same output voltage, what would be the values of the two resistors?How much power would it draw?RL−VOU T+R IOU TVCCFigure 3: Resistor “current source”5. Consider the circuit shown in Figure 3. Let VCC= 10 V and R = 10 kΩ. Roughly sketch IOU Tvs.VOU T.6. Find the short circuit output current and the output impedance of the curr e nt source.3−1−0.8−0.6−0.4−0.200.20.40.60.81IOU T(mA)0 10 20VOU T(V)7. Is it possible to increase the output impedance without decreasing the output current and withoutchanging VCC?
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