In an ac series RC circuit, if 20 VAC is measured across the resistor and 40 VAC is measured across the capacitor, the magnitude of the applied voltage is: (a) ≈ 60 VACĪnswer: The applied voltage is ??? = ?? + ???, so that |??? | = �??2 + ??2 = √2,000 ≈ 45 VAC. Neglecting the diodes’ turn-on voltages, the ripple voltage will: a) b) c) d)ĭecrease by a factor 4 Decrease by a factor 2 Stay the same Increase by a factor 4 The rectifier diode is now replaced with a bridge (4-diode) rectifier. Reduce ripple voltage by 50% and increase maximum inrush current by 50% Reduce both ripple voltage and maximum inrush current by 50% Reduce ripple voltage by 50% and leave maximum inrush current unaffected Reduce ripple voltage by 50% and increase maximum inrush current by 100%Ĭonsider a linear power supply consisting of a transformer, a half-wave, 1-diode rectifier, and a smoothing capacitor. Increasing the smoothing capacitor by 50% will (a) (b) (c) (d) By what percentage will the ripple voltage increase if the load current increases to 1.5 A? a) 100 %Ĭonsider a linear power supply consisting of a transformer, a full-wave, a bridge rectifier and a smoothing capacitor. What is the required peak-to-peak voltage swing across the load? (a) (b) (c) (d) (e)Ģ ⁄ Answer: ? = ???? ?, so that ???? = 5 V, so that ??? = 14.14 V, so (d).Ĭonsider a linear power supply consisting of a transformer, a full-wave, 4-diode bridge rectifier, smoothing capacitor, and a load current 1.2 A.
What is the required peak-to-peak voltage swing across the load? 2 ⁄ Answer: ? = ???? ?, so that ???? = 5 V, so that ??? = 14.14 VĪn engineer designs a MOSFET-based class-AB amplifier to deliver 6.25 W (sinusoidal) signal power to a 4 Ω resistive load. However, the op-amp is powered by a +15-V power supply, so that the output will be clamped to a value close to +15 V, so the answer is (c).Īn engineer designs a MOSFET-based class-AB amplifier to deliver 6.25 W (sinusoidal) signal power to a 4 Ω resistive load. In the circuit shown, the output voltage isĪnswer: This is a non-inverting amplifier with gain (1 + 8⁄2) = 5, so with a 5-V input the output should be 25 V. The output is a square wave for frequency ?⁄2? Hz, so the answer is (b) Triangular wave with frequency ? rad/s Need additional informationĪnswer: With no feedback, the circuit is highly non-linear and operates as a comparator, comparing the input amplitude against 0 V. Sine wave with frequency ? rad/s Square wave with frequency ?⁄2? Hz
The voltage gain of the amplifier shown isĪnswer: ?? = −?? ⁄?1 = 68K⁄12K = 5.7, so the answer is (a) The output of the circuit shown is The bandwidth is 1⁄(2??) = 795.8 Hz, so the answer is (a). (If one turns off ??, ?? ?? = 0, and the current source is effectively removed from the circuit.) The time-constant is ? = ?? = (2 nF)(100K) = 200 ?s. This capacitor sees an equivalent resistance ?? = 100K. What is the 3-dB bandwidth of the amplifier shown below if ?? = 2.5K, ?? = 100K, ?? = 40 mS, and ?? = ?? = 1 nF?Īnswer: If one turns off ??, it is shorted to ground and ?? is in parallel with ?? so the effective capacitance is 2 nF. What is the 3-dB bandwidth of the circuit below?Īnswer: The capacitor sees an equivalent resistance ? = ?2 = 10K (the current source has infinite internal resistance) and the time-constant is ? = ?? = 10 ?s, so that the bandwidth is 1⁄(2??) = 15.92 kHz, and (c) is the answer. Since all the resistors have same value, ???? = −?1 − ?2 = −4 V, so (c) is the answer. In the circuit, ?1 = 1.5 V, ?2 = 2.5 V, and all the resistors have value 20K. This measn the peak value should be 9√2 V, so the peak-to-peak value should be 18√2 = 25.5 V, so the answer is (b). What peak-to-peak amplitude should an ac source have to generate the same power in the resistor? (a) 12.73 VĪnswer: The ac source’s effective (or rms) value should also be 9 V. Homework Assignment 03 Question 1 (2 points each unless noted otherwise)Ī 9-V dc power supply generates 10 W in a resistor.