Question Physics Q Use the feedback analysis tools in the circuit below to calculate: Note that h_fe=100 The voltage gain V_o⁄V_B1 The input impedance at B_1

The output impedance at V_o

Frequency analysis of transistor amplifiers For circuit (a) below, calculate:

R_e and R_C to make I_C≈0.2 mA and V_CE≈6V.

C_e to give a pole frequency at about 400 Hz, and C_C to give a pole at about 50 Hz.

The oscilloscope input resistance is 1 MΩ. For initial calculations assume C_μ= 5 pF and C_(CRO + cable)= 110 pF. (These will be measured in the lab.) The generator resistance is 50 Ω, which may be taken as a good approximation to zero for this experiment. Moreover, the input will be monitored across the generator and its voltage kept constant, so it may be treated as an ideal voltage source.

Estimate the voltage gain, the frequency of the zero introduced by C_e, and the upper 3-dB frequency f_h. What is the voltage gain if C_e is omitted?

Circuit (b) is to be inserted in series at point B to buffer the load capacitance. Calculate R to give a collector current of about 1.2 mA. Assuming a 'typical' value for h_fe, recalculate f_h. Is the pole frequency introduced by C_C significantly affected?

Leaving circuit (b) in place, a 10 kΩ resistor is inserted at point A (simulating a higher source resistance than that of the generator). Recalculate f_h. Is the pole frequency introduced by C_e affected?

Lowpass and Bandpass Filters Design: A second-order VCVS (Sallen & Key) lowpass filter with 1 dB Chebyshev ripple, f_h=7.2 kHz and a gain of 2.

a biquad second-order bandpass filter with f_o adjustable between 1 and 2 kHz, bandwidth 160 Hz and a gain of 10. (Make R_4 a variable resistor).

Append your calculations. You should use common component values such as: 10nF, 2kΩ, 2.2kΩ, 4.7 kΩ, 10kΩ, 10kΩ, and 100kΩ

Plot the theoretical magnitude (dB) and phase response of (1) from 100 Hz to 100 kHz on 4-cycle log paper, and of (2) from f_o⁄2 to 2f_o using a linear frequency axis, with f_o set to 1 and 2 kHz.