2-2

Q.) A dc chopper in figure has a resistive load of R = 10Ω and input voltage of V = 200V. When chopper is ON, its voltage drop is 2 V and the chopping frequency is 1 kHz. If the duty cycle is 60%, determine – Average output voltage– RMS value of output voltage - Effective input resistance of chopper – Chopper efficiency.

What is the DC gain of the given circuit above?

4: Design a buck converter to produce an output voltage of 18 V across a 10-_ load resistor. The output voltage ripple must not exceed 0.5 percent. The dc supply is 48 V. Design for continuous inductor current. Specify the duty ratio, the switching frequency, the values of the inductor and capacitor, the peak voltage rating of each device, and the rms current in the inductor and capacitor. Assume ideal components.

The term duty cycle refers to the amount of time a signal is complete cycle. A. off compared to the period of one B. on The output voltage of op-amp is positive saturation, when the voltage applied to the input is greater than the input. A. inverting B. noninverting A square wave that is 20V at its high state and OV when it is off will produce an average DC when its duty cycle is 75%. Formula: VOUT = Duty Cycle * Peak voltage voltage of A. 7.5V B. 10V C. 15V

If a sinusoidal input voltage of 2 volts peak-to-peak plus a DC offset of +1V is applied as the input voltage of your inverting amplifier, make a sketch showing this input voltage waveform and the expected output voltage waveform on the same plot. Sketch of waveforms:

Consider the circuit in Figure A4. (a) Explain its operation with the aid of diagrams. (b) Assume that R₁ = 21 kQ, Vref = 1.2 V, Vs = +12 V and -Vs = -12 V. Determine a value for R₂ to obtain a maximum threshold voltage of Vth = 5.25 V. (c) Sketch the output voltage signal in time for a sinusoidal input signal of peak voltage 3.5 V and frequency 2 kHz. R1 R2 Vout Vref Vin +Vs -Vs Figure A4

In the common mode, ..... ..... ..... Select one: a. the output signal are in-phase b. an identical signal appears on both the inputs c. the outputs are connected together d. both inputs are grounded

One way to control power, in an electronic system is to using the PWM (pulse width modulation) method. To create an adjustable signal pulse width, one of which is used a window comparator as shown in the figure (VCC = +12 V, VEE = -12 V). If a 10 Vpp 10 kHz signal is given as an input, determine the complete output waveform by displaying the reference voltage. (compare with the input)

14. Derive the expressions of average and rms values of output voltage of step-down/step-up chopper.