Question

A common source amplifier circuit based on a single n-channel MOSFET is shown in Figure 4b. Assume that the transconductance gm-60 mS (equivalent to mA/ V) and drain source resistance, os, is so large it may be neglected. 0) Calculate the open circuit voltage gain Av Yout/ Vis. i) The amplifier has a load of 10 k2. Determine the current gain Va. = 12 V 150k 4k3 Vout Vin 200k GND = 0 V Figure 4b a) State the name of the amplifier circuit shown in Figure 4a, and state its key properties. R, C, C2 R2 Gnd Figure 4a b) Draw an a.c. small signal equivalent circuit for the amplifier using an h (hybrid) parameter model for the transistor in Figure 4b. Justify the components included. Design the value of the e) load resistance, Ri, so that the amplifier provides a current gain of 650 and calculate the output resistance of the amplifier. Assume h-parameter values of his 1 k0 and his- 100. Figure 3b shows a circuit that includes an ideal four terminal amplifier. The input signal ys is a sine wave with peak amplitude of 2 mV, while the amplified output y. b) signal is a sine wave with peak amplitude of 300 mV. Given parameters are: Rs = 2.5 kQ, Rin = 2 MQ, Rout-20 Ω and RL = 100 Ω i) Calculate the amplifief gain Av. ii) Design Rin and Rout to maximise the power delivered to the load R. Clearly show all your working. A, Rs lout in Figure 3b The generic voltage amplifier shown in Figure 3a has the following parameters: Cs-2μF, Rin-25 kQ, Av-2500, CL 1 μF and Rout-15 Ω Cs Rout Av Figure 3a i) Calculate the input circuit cutoff frequency, (oin or/v i) Sketch the frequency response of the input circuit ie. Ivivl as a function of ω on log-scale. Note that ω is angular frequency in rad/s (ω-2rf, f is frequency). ii) Calculate the output circuit cutoff frequency, Oout for vi/Voudl iv) Sketch the frequency response of the output circuit i.e. vi/Voul as a function of ω on log-scale. Is this a high or low pass filter? v) Using the cutoff frequencies and frequency responses above, draw the frequency response for the whole amplifier i.e. a Bode plot (︺vsl versus ω on log-scale). inn 3 continues averleaf c) The excitation voltage of the circuit shown in Figure 2c is v, 15 x sin (100rt). Assume the diode is ideal (Gi) Sketch the voltage waveform between points A and B of this circuit. (i) State one possible application for this circuit 3 V Figure 2c 2. a) You have been asked to design the voltage regulator circuit shown in Figure 2b. A power supply (V.) varies from 10 V to 12 Y, and is used to power a cassette recorder. If the breakdown voltage of the Zener diode is 8 V and the cassette recorder draws a current of 10 mA when playing and 0 mA when paused, calculate: R, 40 8 V Figure 2b (i) The nominal voltage VAB. (ii) The maximum current across the Zener diode. (ii) The minimum current across the Zener diode. (iv) The variation in the voltage across AB, assuming that the Zener diode has a dynamic breakdown resistance of 5 2 A LED has been designed to emit light at a wavelength of 600 nm. Calculate the band b) gap energy (in eV) of the semiconductor material required for this device. f) For the circuit of Figure 1f determine approximate values for each of the five quantities: 1, 12, 13, VB and VCE. For the transistor β-: 200, Assume that the collector and emitter currents are the same. Ignore the effect of Iz on VB. State the operational mode of the transistor and give your reasons. What is the operating point of this circuit? 20k 4k2 CE out in 10k 6k2 GND 0 V Figure 1f b) Sketch the current - voltage characteristics for a typical silicon diode over the voltage range -2 V to +2 V. Explain how the characteristics would change if the diode was fabricated using germanium. Give an equivalent circuit representation of the device in each case. c) In a silicon diode a cument of 200 μΑ flows when a forward bias voltage of 0.5 V is applied at room temperature. Calculate the reverse saturation current of the diode. Assume that the ideality factor of the diode is 1. d) Explain briefly how an n-channel enhancement metal oxide semiconductor field effect transistor (MOSFET) operates. e) An n-channel enhancement MOSFET is used as an inverter and connected as shown in Figure le. The MOSFET has a threshold voltage VT -0.8 V and the transconductance gm (in saturation) = 2 mA / V. Design the minimum value of drain resistance Rp required to set the output voltage for logic 0 of the inverter, V, at 0.2 V 3 V RD o V Vi o V Figure le

Answer 1

Note: According to HomeworkLib policy we have to answer for the first four parts only.thanku

含S -t th

Since It is also called Shitta-t-dlawlMVatnge Cin orderm

3 lb e Vec e - le