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Operational Amplifiers · CAPE Physics Unit 2

243 past-paper questions on Operational Amplifiers, part of AC Theory and Electronics, from every CAPE Physics Unit 2 paper on Quelpr.

Practise Operational Amplifiers
  1. 2(a)3 marks· CAPE Physics Unit 2 · 2001 · Paper 2Draw a circuit diagram to show how the operational amplifier could be used over a wider range of frequencies at a reduced gain.
  2. 2(b)1 mark· CAPE Physics Unit 2 · 2001 · Paper 2State what feature allows the gain to be reduced.
  3. 2(c)2 marks· CAPE Physics Unit 2 · 2001 · Paper 2State what adjustment can be made to your circuit to lower the gain.
  4. 2(d)2 marks· CAPE Physics Unit 2 · 2001 · Paper 2State what effect(s) this would have on the amplifier.
  5. 2(e)2 marks· CAPE Physics Unit 2 · 2001 · Paper 2Given that the closed loop gain is related to the open loop gain by A = A_0 / (1 + β A_0), where β is a negative fraction of output fed back to the input, calculate the value of β when A_0 = 10^5 and A = 10^2.
  6. 7(a)3 marks· CAPE Physics Unit 2 · 2001 · Paper 2Give THREE properties of an ideal operational amplifier.
  7. 7(b)5 marks· CAPE Physics Unit 2 · 2001 · Paper 2For the non-inverting amplifier shown in Figure 4, show that the closed loop voltage gain, A, is given by A = 1 + R_f / R_i.
  8. 7(c)(i)1 mark· CAPE Physics Unit 2 · 2001 · Paper 2Determine the closed loop gain.
  9. 7(c)(ii)2 marks· CAPE Physics Unit 2 · 2001 · Paper 2When this circuit is used it saturates at ±13 V. If saturation is to be avoided, calculate the maximum input voltage that can be used.
  10. 7(c)(iii)2 marks· CAPE Physics Unit 2 · 2001 · Paper 2Determine the output voltage for a sinusoidal signal of peak input voltage 3 V.
  11. 7(c)(iv)2 marks· CAPE Physics Unit 2 · 2001 · Paper 2Sketch the resulting output signal when the peak input voltage is 3 V.
  12. 7(d)5 marks· CAPE Physics Unit 2 · 2001 · Paper 2Design an op-amp summing circuit to combine three signals V_1, V_2, and V_3 to produce V_0 = -V_1 - 4V_2 - 12V_3, such that the input resistance at the inputs is not less than 10 kΩ and all resistor values are less than…
  13. 4(a)5 marks· CAPE Physics Unit 2 · 2002 · Paper 1Determine the gain of the amplifier.
  14. 4(b)(i)1 mark· CAPE Physics Unit 2 · 2002 · Paper 1Write down the name of the operational amplifier circuit shown in Figure 5.
  15. 4(b)(ii)2 marks· CAPE Physics Unit 2 · 2002 · Paper 1State TWO practical uses of the circuit shown in Figure 5.
  16. 4(c)2 marks· CAPE Physics Unit 2 · 2002 · Paper 1State how the values of V_o1 and V_o2 relate to V_1.
  17. 6(a)(i)3 marks· CAPE Physics Unit 2 · 2002 · Paper 2State THREE ideal properties of operational amplifiers (Op-Amps).
  18. 6(a)(ii)3 marks· CAPE Physics Unit 2 · 2002 · Paper 2For the Op-Amp circuit shown in Figure 8, show that the output voltage is given by Vo = - (Rf / R1) V1 - (Rf / R2) V2.
  19. 6(a)(iii)1 mark· CAPE Physics Unit 2 · 2002 · Paper 2Suggest a practical use for this summing amplifier circuit.
  20. 7(a)5 marks· CAPE Physics Unit 2 · 2002 · Paper 2Explain the shape of the gain-frequency response curve for an operational amplifier shown in Figure 10.
  21. 5(a)3 marks· CAPE Physics Unit 2 · 2003 · Paper 1In the space provided, sketch a typical gain frequency curve for an operational amplifier.
  22. 5(b)1 mark· CAPE Physics Unit 2 · 2003 · Paper 1What is meant by a 'virtual earth' in an operational amplifier circuit?
  23. 5(c)1 mark· CAPE Physics Unit 2 · 2003 · Paper 1State ONE effect of positive feedback in an operational amplifier circuit.
  24. 5(d)(i)4 marks· CAPE Physics Unit 2 · 2003 · Paper 1Calculate the net gain of the circuit.
  25. 5(d)(ii)1 mark· CAPE Physics Unit 2 · 2003 · Paper 1Calculate the output voltage, V_0, when V_i = 0.01 V.
  26. 2(a)2 marks· CAPE Physics Unit 2 · 2003 · Paper 2Determine the theoretical gain of the amplifier shown in Figure 2.
  27. 2(b)4 marks· CAPE Physics Unit 2 · 2003 · Paper 2On the graph page on page 7, plot a graph of V_o versus V_i using the data in Table 1.
  28. 2(c)(i)2 marks· CAPE Physics Unit 2 · 2003 · Paper 2From your graph, determine the gradient of the linear section.
  29. 2(c)(ii)1 mark· CAPE Physics Unit 2 · 2003 · Paper 2From your graph, determine the gain of the operational amplifier.
  30. 2(c)(iii)1 mark· CAPE Physics Unit 2 · 2003 · Paper 2From your graph, determine the saturation voltages of the operational amplifier.
  31. 6(a)(i)6 marks· CAPE Physics Unit 2 · 2003 · Paper 2State THREE characteristics of the ideal operational amplifier and their implications for the ideal operational amplifier.
  32. 6(a)(ii)2 marks· CAPE Physics Unit 2 · 2003 · Paper 2What effect does negative feedback have on the gain and bandwidth of an operational amplifier?
  33. 6(b)(i)3 marks· CAPE Physics Unit 2 · 2003 · Paper 2Determine the output voltage, V_o, of the circuit.
  34. 6(b)(ii)1 mark· CAPE Physics Unit 2 · 2003 · Paper 2Suggest a practical use for circuit B.
  35. 6(b)(iii)3 marks· CAPE Physics Unit 2 · 2003 · Paper 2The entire circuit in Figure 6 saturates at +- 13 V. What is the maximum input voltage that will NOT saturate this circuit?
  36. 6(c)5 marks· CAPE Physics Unit 2 · 2003 · Paper 2Three signals V_1, V_2 and V_3 are to be combined to produce an output V_o = -3V_1 - V_2 - 5V_3. The input resistance of the inputs must NOT be less than 10 kOmega and all resistor values must be less than 200 kOmega.…
  37. 6(a)(i)1 mark· CAPE Physics Unit 2 · 2004 · Paper 1Explain the effect of negative feedback on the gain of an operational amplifier.
  38. 6(a)(ii)1 mark· CAPE Physics Unit 2 · 2004 · Paper 1Explain the effect of negative feedback on the bandwidth of an operational amplifier.
  39. 6(b)(i)4 marks· CAPE Physics Unit 2 · 2004 · Paper 1Draw an inverting amplifier circuit with input resistance Ri and feedback resistance Rf, and use it to explain what is meant by a virtual ground.
  40. 6(b)(ii)1 mark· CAPE Physics Unit 2 · 2004 · Paper 1Calculate the voltage at point A in Figure 6.
  41. 6(b)(iii)2 marks· CAPE Physics Unit 2 · 2004 · Paper 1Calculate the output voltage Vo in Figure 6.
  42. 6(b)(iv)1 mark· CAPE Physics Unit 2 · 2004 · Paper 1Calculate the overall gain of the circuit in Figure 6.
  43. 6(a)(i)4 marks· CAPE Physics Unit 2 · 2004 · Paper 2Show that the closed loop voltage gain, A, in the circuit is given by A = 1 + R_f / R_i.
  44. 6(a)(ii)2 marks· CAPE Physics Unit 2 · 2004 · Paper 2Explain how the circuit differs from that of an inverting amplifier circuit.
  45. 6(a)(iii)2 marks· CAPE Physics Unit 2 · 2004 · Paper 2State what the input impedance of the non-inverting amplifier is.
  46. 6(b)2 marks· CAPE Physics Unit 2 · 2004 · Paper 2The saturation voltage of the non-inverting amplifier is 15 V. If R_f = 100 kΩ and R_i = 50 kΩ, determine the maximum input voltage, v_i, such that saturation just occurs.
  47. 6(c)6 marks· CAPE Physics Unit 2 · 2004 · Paper 2Determine the value of R_f and the range of the rheostat R_s.
  48. 6(d)4 marks· CAPE Physics Unit 2 · 2004 · Paper 2Design a circuit to combine two signals v_1 and v_2 to form an output v_o = -v_1 - 20v_2, where the minimum input resistance for both signal inputs is no less than 10 kΩ.
  49. 4(a)3 marks· CAPE Physics Unit 2 · 2005 · Paper 1State THREE properties of the ideal operational amplifier (op - amp).
  50. 4(b)(i)2 marks· CAPE Physics Unit 2 · 2005 · Paper 1Calculate the positive and negative input voltages at which saturation will be reached.
  51. 4(b)(iii)4 marks· CAPE Physics Unit 2 · 2005 · Paper 1On the axes provided, sketch both the input voltage V_i and the output voltage V_o for TWO complete cycles, clearly indicating maximum voltages and periodic times on the axes.
  52. 2(a)1 mark· CAPE Physics Unit 2 · 2005 · Paper 2What is the gain of this amplifier at low frequencies?
  53. 2(b)3 marks· CAPE Physics Unit 2 · 2005 · Paper 2Using the CRO display where the output sensitivity is 1 V/div and input is 10 mV/div, calculate the gain, A, of the amplifier for this frequency.
  54. 2(c)3 marks· CAPE Physics Unit 2 · 2005 · Paper 2The graph on page 8 shows experimental gain data against frequency. Use the graph to complete Table 2.
  55. 2(d)(i)1 mark· CAPE Physics Unit 2 · 2005 · Paper 2What is the bandwidth of the amplifier?
  56. 2(d)(ii)2 marks· CAPE Physics Unit 2 · 2005 · Paper 2If the value of input resistance R_1 is changed to 1.0 kOmega, state how the low frequency gain and bandwidth of the amplifier will change.
  57. 4(a)(i)2 marks· CAPE Physics Unit 2 · 2006 · Paper 1Write the formula for the gain of amplifier A and amplifier B.
  58. 4(a)(ii)1 mark· CAPE Physics Unit 2 · 2006 · Paper 1Mark with an X any point or points on the circuit diagram that act as a virtual earth.
  59. 4(a)(iii)3 marks· CAPE Physics Unit 2 · 2006 · Paper 1If the input voltage is 0.3 V, determine the output voltage V_out.
  60. 4(b)4 marks· CAPE Physics Unit 2 · 2006 · Paper 1Design a circuit using an operational amplifier and resistors with values between 15 kΩ and 200 kΩ to combine three signals V_1, V_2, and V_3 to yield V_out = -2V_1 - 8V_2 - V_3.
  61. 6(b)3 marks· CAPE Physics Unit 2 · 2006 · Paper 1Draw a graph on the axes in Figure 8 showing how the output voltage varies with time, indicating the vertical scale clearly.
  62. 2(a)4 marks· CAPE Physics Unit 2 · 2006 · Paper 2Use the data in Table 2 to plot the transfer characteristic (V_{\text{out}} versus V_{\text{in}}) of the amplifier on the graph sheet provided.
  63. 2(b)2 marks· CAPE Physics Unit 2 · 2006 · Paper 2Determine the gradient of the linear region of the graph.
  64. 2(c)(i)2 marks· CAPE Physics Unit 2 · 2006 · Paper 2If R_1 is 10\text{ k}\Omega, what is the resistance of R_2?
  65. 2(c)(ii)2 marks· CAPE Physics Unit 2 · 2006 · Paper 2What is the largest positive input voltage which can be used if the amplifier is not saturated?
  66. 6(a)(i)1 mark· CAPE Physics Unit 2 · 2006 · Paper 2Explain why the scales on the axes are logarithmic rather than linear.
  67. 6(a)(ii)1 mark· CAPE Physics Unit 2 · 2006 · Paper 2What value does the graph give for the open loop gain of the op-amp.?
  68. 6(b)(i)1 mark· CAPE Physics Unit 2 · 2006 · Paper 2Use the graph to determine its bandwidth.
  69. 6(b)(ii)2 marks· CAPE Physics Unit 2 · 2006 · Paper 2Draw a circuit diagram to show how the non-inverting amplifier could be constructed.
  70. 6(b)(iii)1 mark· CAPE Physics Unit 2 · 2006 · Paper 2Write the formula for the gain of this amplifier.
  71. 6(b)(iv)2 marks· CAPE Physics Unit 2 · 2006 · Paper 2State the ratio of the feedback resistance to resistance of the input resistor in this non-inverting amplifier.
  72. 6(c)2 marks· CAPE Physics Unit 2 · 2006 · Paper 2Using your answer to (a) above determine the maximum input voltage to the op-amp. if it is not saturated.
  73. 6(d)(ii)4 marks· CAPE Physics Unit 2 · 2006 · Paper 2In the dark the resistance of the light-dependent resistor (ldr) is 400\text{ k}\Omega. Find the potential at the inverting terminal in this situation and use this value to explain why the light emitting diode (led)…
  74. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2007 · Paper 1The figure shows an op-amp used as a comparator. The open loop voltage gain of the op-amp is 3 \times 10^5 and the voltage of the power supply is \pm 6\text{ V}. The MINIMUM input voltage (V_i) which will cause…
  75. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2007 · Paper 1Which of the following is NOT an advantage of using negative feedback in an op-amp?
  76. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2007 · Paper 1Which diagram shows the circuit for a non-inverting amplifier?
  77. Q251 mark · multiple choice· CAPE Physics Unit 2 · 2007 · Paper 1The gain of the op-amp circuit in the diagram above is
  78. Q261 mark · multiple choice· CAPE Physics Unit 2 · 2007 · Paper 1The sinusoidal alternating voltage shown in Figure 2 is applied to the input of the op-amp shown in Figure 1. The voltage of the power supply is \pm 10\text{ V}. Which one of the following graphs correctly shows…
  79. 2(b)(ii)3 marks· CAPE Physics Unit 2 · 2007 · Paper 2State, with reasons, whether the LED will be ON or OFF when the temperature of the thermistor is 75 °C.
  80. 2(b)(iii)2 marks· CAPE Physics Unit 2 · 2007 · Paper 2Determine the temperature at which the LED turns on as the temperature is increased from 40 °C.
  81. 7(c)(iii)a)2 marks· CAPE Physics Unit 2 · 2007 · Paper 2Write an equation expressing the output voltage V_out in terms of the input voltages V_x, V_y, and V_z.
  82. 7(c)(iii)b)3 marks· CAPE Physics Unit 2 · 2007 · Paper 2Calculate the value of V_out for the binary inputs (Z, Y, X): (i) 001, (ii) 101, and (iii) 110.
  83. 7(c)(iii)c)2 marks· CAPE Physics Unit 2 · 2007 · Paper 2Briefly explain how this circuit functions as a digital-to-analogue converter (DAC).
  84. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2007 (Specimen) · Paper 1Which pair of values gives the open-loop gain of an ideal op. amp. and that of a typical op. amp.
  85. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2007 (Specimen) · Paper 1Which of the following represents the gain of the amplifier?
  86. Q251 mark · multiple choice· CAPE Physics Unit 2 · 2007 (Specimen) · Paper 1The gain of the op-amp in the diagram above is
  87. Q261 mark · multiple choice· CAPE Physics Unit 2 · 2007 (Specimen) · Paper 1The sinusoidal alternating voltage shown in Figure 2 is applied to the input of the op-amp shown in Figure 1. The voltage of the power supply is \pm 6\text{V}. Which one of the following graphs correctly shows the…
  88. Q271 mark · multiple choice· CAPE Physics Unit 2 · 2007 (Specimen) · Paper 1Which of the following statements does NOT apply to the op-amp in the diagram above? The op-amp circuit
  89. Q211 mark · multiple choice· CAPE Physics Unit 2 · 2008 (Rest of Region) · Paper 1In the circuit above, the value of V_o is
  90. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2008 (Rest of Region) · Paper 1What is the gain of the amplifier shown above?
  91. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2008 (Rest of Region) · Paper 1The bandwidth associated with a gain of 400 is
  92. 5(a)5 marks· CAPE Physics Unit 2 · 2008 (Rest of Region) · Paper 2Derive the equation for the gain of an inverting amplifier A = -R_2 / R_1, clearly stating two necessary assumptions about the operational amplifier.
  93. 5(b)10 marks· CAPE Physics Unit 2 · 2008 (Rest of Region) · Paper 2Plot a suitable graph of the provided data for R_1 and A to determine whether the gain formula applies, and write a concise summary with reasoning.
  94. Q211 mark · multiple choice· CAPE Physics Unit 2 · 2008 (T&T) · Paper 1Which of the labelled points could be called a virtual earth?
  95. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2008 (T&T) · Paper 1What is the output, V_o, of the amplifier?
  96. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2008 (T&T) · Paper 1Item 23 refers to the following diagram which shows an amplifier. If V_s = \pm 9\text{ V}, what is the value of V_o?
  97. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2008 (T&T) · Paper 1Item 24 refers to the following diagram. In the circuit shown an a.c. signal with an amplitude of 3\text{ V} is applied to the non-inverting terminal of the op. amp. By means of the potential divider the potential at…
  98. 2(a)(i)2 marks· CAPE Physics Unit 2 · 2008 (T&T) · Paper 2Suggest a pair of values for the resistors, R_1 and R_2, if the amplifier is to have a gain of +10.
  99. 2(a)(ii)4 marks· CAPE Physics Unit 2 · 2008 (T&T) · Paper 2State what extra equipment would be needed to obtain data to plot the amplifier's transfer characteristic (graph of V_out vs V_in), and show on Figure 3 how these components would be connected.
  100. 2(b)(i)5 marks· CAPE Physics Unit 2 · 2008 (T&T) · Paper 2Use the data in Table 1 to plot, on the grid provided, the transfer characteristic for the non-inverting amplifier.
  101. 2(b)(ii)2 marks· CAPE Physics Unit 2 · 2008 (T&T) · Paper 2From your graph determine the gain of the amplifier.
  102. 2(b)(iii)2 marks· CAPE Physics Unit 2 · 2008 (T&T) · Paper 2State the range of possible input voltages if the amplifier is NOT to be saturated (maximum positive input and maximum negative input).
  103. Q211 mark · multiple choice· CAPE Physics Unit 2 · 2009 · Paper 1Which one of the circuits below is NOT a non-inverting amplifier?
  104. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2009 · Paper 1Item 22 refers to the following diagram which shows an amplifier. If V_s = \pm 9\text{ V} what is the value of V_o?
  105. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2009 · Paper 1Item 23 refers to the following diagram. From the information given in the operational amplifier circuit above, determine the current in the 6.0\text{ k}\Omega load resistor.
  106. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2009 · Paper 1Item 24 refers to the following diagram. The circuit above represents
  107. Q251 mark · multiple choice· CAPE Physics Unit 2 · 2009 · Paper 1Item 25 refers to the following diagram. In the operational amplifier circuit shown above, the feedback resistor (R_f) serves to
  108. Q261 mark · multiple choice· CAPE Physics Unit 2 · 2009 · Paper 1Item 26 refers to the following diagrams. The sinusoidal alternating voltage shown in Figure 2 is applied to the input of the operational amplifier shown in Figure 1. The voltage of the power supply is $\pm 15\text{…
  109. 5(a)(i)1 mark· CAPE Physics Unit 2 · 2009 · Paper 2State the type of amplifier configuration shown in Figure 7.
  110. 5(a)(ii)2 marks· CAPE Physics Unit 2 · 2009 · Paper 2Explain what is meant by 'negative feedback'.
  111. 5(a)(iii)2 marks· CAPE Physics Unit 2 · 2009 · Paper 2Calculate the bandwidth of the amplifier circuit shown in Figure 7.
  112. 5(b)(i)2 marks· CAPE Physics Unit 2 · 2009 · Paper 2Calculate the peak output voltage when the frequency is 500 Hz.
  113. 5(b)(ii)2 marks· CAPE Physics Unit 2 · 2009 · Paper 2Calculate the peak output voltage when the frequency is 10 000 Hz.
  114. 5(c)(ii)2 marks· CAPE Physics Unit 2 · 2009 · Paper 2Find the output of the amplifier at t = 5 ms.
  115. 5(c)(iii)3 marks· CAPE Physics Unit 2 · 2009 · Paper 2Sketch a graph showing the shape of the output waveform from the amplifier.
  116. Q211 mark · multiple choice· CAPE Physics Unit 2 · 2010 · Paper 1If V_s = \pm 9\text{ V} what is the value of V_o?
  117. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2010 · Paper 1Which of the following options is correct for a non-inverting amplifier circuit constructed using an operational amplifier?
  118. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2010 · Paper 1An operational amplifier circuit has a gain of 10^3 and a bandwidth of 10^3\text{ Hz}. What is the approximate bandwidth when the gain is reduced to 10?
  119. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2010 · Paper 1Which of the labelled points could be called a virtual earth?
  120. Q251 mark · multiple choice· CAPE Physics Unit 2 · 2010 · Paper 1From the information given in the operational amplifier circuit above, determine the magnitude of the current through the feedback resistor.
  121. Q271 mark · multiple choice· CAPE Physics Unit 2 · 2010 · Paper 1Which of the following statements is correct for the amplifier in the diagram above?
  122. 5(a)5 marks· CAPE Physics Unit 2 · 2010 · Paper 2Show that the closed loop gain, A, of the non-inverting operational amplifier circuit in Figure 4 is given by A = (R_i + R_f) / R_i. Clearly state any assumptions made about the properties of the op-amp.
  123. 5(b)(i)1 mark· CAPE Physics Unit 2 · 2010 · Paper 2What is the value of the output voltage when V_i = +250 mV?
  124. 5(b)(ii)2 marks· CAPE Physics Unit 2 · 2010 · Paper 2If the op-amp is NOT to be saturated, what is the MAXIMUM voltage amplitude for the input signal?
  125. 5(b)(iii)3 marks· CAPE Physics Unit 2 · 2010 · Paper 2Sketch a graph to show the expected output when a sinusoidal signal with an amplitude of 0.75 V is applied to the input of this amplifier.
  126. 5(c)4 marks· CAPE Physics Unit 2 · 2010 · Paper 2In a certain application, it is desired to combine two signals, v₁ and v₂, to form a signal v₀ according to the relation v₀ = -2 v₁ - 5 v₂. The minimum input resistance for both signal inputs should be NO less than 10.0…
  127. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2011 · Paper 1From the information given in the operational amplifier circuit above, determine the current in the 6.0\text{ k}\Omega load resistor.
  128. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2011 · Paper 1The gain of an inverting amplifier constructed using this operational amplifier is 10^3. What is the bandwidth of this amplifier?
  129. Q251 mark · multiple choice· CAPE Physics Unit 2 · 2011 · Paper 1Which of the following gain-frequency graphs represents that of an ideal operational amplifier?
  130. 5(a)(i)2 marks· CAPE Physics Unit 2 · 2011 · Paper 2Explain the terms 'bandwidth' and 'feedback' as applied to operational amplifiers (op-amps).
  131. 5(a)(ii)3 marks· CAPE Physics Unit 2 · 2011 · Paper 2Sketch, on the same axes, the input waveform and the output waveform produced from the open-loop op-amp circuit in Figure 5 (a).
  132. 5(a)(iii)2 marks· CAPE Physics Unit 2 · 2011 · Paper 2Explain the shape of the waveform shown in Figure 5 (b) when a constant voltage of 0.5 V is applied to non-inverting terminal Q.
  133. 5(b)(i)3 marks· CAPE Physics Unit 2 · 2011 · Paper 2Draw the resulting circuit and state the name of this type of circuit.
  134. 5(b)(ii)3 marks· CAPE Physics Unit 2 · 2011 · Paper 2Calculate the voltage gain of the circuit.
  135. 5(b)(iii)2 marks· CAPE Physics Unit 2 · 2011 · Paper 2Calculate the MAXIMUM input voltage for no saturation at the output.
  136. Q211 mark · multiple choice· CAPE Physics Unit 2 · 2012 · Paper 1If V_s = \pm 9\text{ V}, what is the value of V_{\text{out}} when the input voltage is 1.2\text{ V}?
  137. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2012 · Paper 1The values for the resistors may be changed. Which of the following pairs of values for R_1 and R_2 would give the amplifier the LARGEST bandwidth?
  138. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2012 · Paper 1An operational amplifier circuit has a gain of 10^3 and a bandwidth of 10^3\text{ Hz}. What is the approximate bandwidth when the gain is reduced to 10?
  139. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2012 · Paper 1What are the possible values of R_1, R_2 and R_3 if the output voltage, V_{\text{out}} = -(3V_1 + 4V_2)?
  140. Q251 mark · multiple choice· CAPE Physics Unit 2 · 2012 · Paper 1From the information given in the operational amplifier circuit above, determine the magnitude of the current through the feedback resistor.
  141. Q261 mark · multiple choice· CAPE Physics Unit 2 · 2012 · Paper 1The sinusoidal alternating voltage shown in Figure 2 is applied to the input of the operational amplifier shown in Figure 1. The voltage of the power supply is \pm 15\text{ V}. Which of the following graphs correctly…
  142. 2(a)(i)3 marks· CAPE Physics Unit 2 · 2012 · Paper 2Add a resistor to the op-amp circuit in Figure 3 so it becomes a non-inverting amplifier with a theoretical gain of +10, and label it with the required resistance value.
  143. 2(a)(ii)3 marks· CAPE Physics Unit 2 · 2012 · Paper 2Show on Figure 3 how meters and a potential divider would be connected to enable data collection of Vin and Vout.
  144. 2(b)(i)6 marks· CAPE Physics Unit 2 · 2012 · Paper 2On the grid provided on page 7, plot the characteristic curve of Vout vs Vin for the non-inverting amplifier using data from Table 1.
  145. 2(b)(ii)3 marks· CAPE Physics Unit 2 · 2012 · Paper 2From the plotted graph, determine the gain of the amplifier to 3 significant figures.
  146. 5(a)(i)1 mark· CAPE Physics Unit 2 · 2012 · Paper 2State the type of amplifier circuit shown in Figure 7.
  147. 5(a)(ii)1 mark· CAPE Physics Unit 2 · 2012 · Paper 2State what is meant by 'negative feedback' in this amplifier.
  148. 5(a)(iii)a)2 marks· CAPE Physics Unit 2 · 2012 · Paper 2Calculate the gain of this amplifier at low frequencies.
  149. 5(a)(iii)b)3 marks· CAPE Physics Unit 2 · 2012 · Paper 2Calculate the bandwidth of the amplifier using Figures 6 and 7.
  150. 5(a)(iv)2 marks· CAPE Physics Unit 2 · 2012 · Paper 2What is the peak output voltage for an input signal of peak value 0.052 V and frequency 1.0 x 10^4 Hz?
  151. Q201 mark · multiple choice· CAPE Physics Unit 2 · 2013 · Paper 1If V_s = \pm 9\text{ V} what is the value of V_o?
  152. Q211 mark · multiple choice· CAPE Physics Unit 2 · 2013 · Paper 1Which one of the circuits is NOT a non-inverting amplifier?
  153. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2013 · Paper 1Which of the labelled points could be called a virtual earth?
  154. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2013 · Paper 1From the information given in the operational amplifier circuit, the current in the 6.0\text{ k}\Omega load resistor is
  155. Q271 mark · multiple choice· CAPE Physics Unit 2 · 2013 · Paper 1The sinusoidal alternating voltage shown in Figure 2 is applied to the input of the operational amplifier shown in Figure 1. The voltage of the power supply is \pm 15\text{ V}. Which one of the following graphs…
  156. Q281 mark · multiple choice· CAPE Physics Unit 2 · 2013 · Paper 1Which of the following statements is correct about the amplifier in the diagram above?
  157. 2(a)(i)1 mark· CAPE Physics Unit 2 · 2013 · Paper 2Use the graph to determine the open loop d.c. gain of the amplifier.
  158. 2(a)(ii)1 mark· CAPE Physics Unit 2 · 2013 · Paper 2Use the graph to determine the unity gain bandwidth of the amplifier.
  159. 2(a)(iii)1 mark· CAPE Physics Unit 2 · 2013 · Paper 2Use the graph to determine the open loop bandwidth of the amplifier.
  160. 2(b)(i)3 marks· CAPE Physics Unit 2 · 2013 · Paper 2Draw the circuit diagram for this amplifier and label the resistors with their values.
  161. 2(b)(ii)2 marks· CAPE Physics Unit 2 · 2013 · Paper 2Calculate the gain of the amplifier.
  162. 2(b)(iii)2 marks· CAPE Physics Unit 2 · 2013 · Paper 2Use the open loop gain-frequency curve in Figure 2 to determine the closed loop bandwidth of this amplifier.
  163. 2(b)(iv)2 marks· CAPE Physics Unit 2 · 2013 · Paper 2Deduce the gain of the amplifier when the input resistance is made infinitely large (effectively removed from the circuit).
  164. 2(b)(v)1 mark· CAPE Physics Unit 2 · 2013 · Paper 2What would be the input impedance of the resulting circuit?
  165. 2(b)(vi)2 marks· CAPE Physics Unit 2 · 2013 · Paper 2Identify the practical application for the circuit and state why it is suited for this application.
  166. 5(b)(i)3 marks· CAPE Physics Unit 2 · 2013 · Paper 2In this circuit, the open loop operational amplifier is used to compare the surrounding lighting level with a preset value. Explain how this is done.
  167. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2014 · Paper 1An operational amplifier circuit has a gain of 10^5 and a bandwidth of 10^3\text{ Hz}. What is the approximate bandwidth when the gain is reduced to 10?
  168. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2014 · Paper 1Which of the following gain–frequency graphs BEST represents that of an ideal operational amplifier?
  169. Q251 mark · multiple choice· CAPE Physics Unit 2 · 2014 · Paper 1From the information given in the operational amplifier circuit above, the current in the 6.0\text{ k}\Omega load resistor is
  170. Q261 mark · multiple choice· CAPE Physics Unit 2 · 2014 · Paper 1What are the possible values of R_1, R_2 and R_3 if the output voltage, V_{\text{out}} = -(3V_1 + 4V_2)?
  171. Q271 mark · multiple choice· CAPE Physics Unit 2 · 2014 · Paper 1Which of the following features relates to the amplifier in the diagram above?
  172. Q281 mark · multiple choice· CAPE Physics Unit 2 · 2014 · Paper 1The values for the resistors may be changed. Which of the following pairs of values for R_1 and R_2 would give the amplifier the LARGEST bandwidth?
  173. Q191 mark · multiple choice· CAPE Physics Unit 2 · 2015 · Paper 1The supply voltage to the op-amp is \pm 9\text{ V}. If the open loop gain is 10^5, what is the maximum input voltage swing for linear amplification?
  174. Q201 mark · multiple choice· CAPE Physics Unit 2 · 2015 · Paper 1If the input voltages, V_1 and V_2, are given as 2\,\mu\text{V} and 6\,\mu\text{V} respectively and the open loop gain is A_0, what is the value of V_0?
  175. Q211 mark · multiple choice· CAPE Physics Unit 2 · 2015 · Paper 1The gain of this amplifier is given by
  176. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2015 · Paper 1Which of the labelled points could be called a virtual earth?
  177. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2015 · Paper 1Given that V_{\text{in}} = 6\,\mu\text{V}, what is the output, V_{\text{out}}, of the cascaded amplifiers?
  178. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2015 · Paper 1What would be the output, V_0, given that V_1 = V_3 = 1\text{ V}, and V_2 = 0?
  179. Q251 mark · multiple choice· CAPE Physics Unit 2 · 2015 · Paper 1The circuit represents
  180. Q271 mark · multiple choice· CAPE Physics Unit 2 · 2015 · Paper 1The sinusoidal alternating voltage shown in Diagram 2 is applied to the input of the operational amplifier shown in Diagram 1. The voltage of the power supply is \pm 15\text{ V}. Which of the following graphs…
  181. 2(a)(i)3 marks· CAPE Physics Unit 2 · 2015 · Paper 2Draw the circuit diagram for an inverting amplifier using an operational amplifier. Label EACH resistor in your circuit with the conventional term used to describe it.
  182. 2(a)(ii)3 marks· CAPE Physics Unit 2 · 2015 · Paper 2State THREE properties of an ideal operational amplifier.
  183. 2(b)(i)4 marks· CAPE Physics Unit 2 · 2015 · Paper 2On the grid provided in Figure 4, plot a graph of output voltage (V_o) vs input voltage (V_i).
  184. 2(b)(ii)2 marks· CAPE Physics Unit 2 · 2015 · Paper 2Use your graph to calculate the gain of the amplifier.
  185. 2(b)(iii)3 marks· CAPE Physics Unit 2 · 2015 · Paper 2Explain the shape of your graph.
  186. Q211 mark · multiple choice· CAPE Physics Unit 2 · 2016 · Paper 1Which of the following gain–frequency graphs BEST represents that of an ideal operational amplifier?
  187. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2016 · Paper 1The gain of the op-amp is 10^4. If the input voltage, V_{\text{in}}, is 10\ \mu\text{V}, what is the MAXIMUM output voltage?
  188. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2016 · Paper 1An operational amplifier circuit has a gain of 10^5 and a bandwidth of 10^3\text{ Hz}. What is the approximate bandwidth when the gain is reduced to 10?
  189. Q251 mark · multiple choice· CAPE Physics Unit 2 · 2016 · Paper 1The values for the resistors may be changed. Which of the following pairs of values for R_1 and R_2 would give the amplifier the LARGEST bandwidth?
  190. Q261 mark · multiple choice· CAPE Physics Unit 2 · 2016 · Paper 1What is the output voltage, V_{\text{out}}, of the op-amp in terms of V_1, V_2 and V_3?
  191. 2(a)6 marks· CAPE Physics Unit 2 · 2016 · Paper 2Draw the circuit diagram and derive the expression for the gain of a non-inverting amplifier.
  192. 2(b)2 marks· CAPE Physics Unit 2 · 2016 · Paper 2The circuit shown in Figure 3 is used in a tester for resistive transducers. Show that output voltage V_o and R_x are related by the equation V_o = 30\,000\, R_x^{-1} - 10, where R_3 = R_2 = 10\text{ k}\Omega,…
  193. 2(c)(i)1 mark· CAPE Physics Unit 2 · 2016 · Paper 2Complete Table 2 by inserting the appropriate values in Column 2 for R_x^{-1} (10^{-3}).
  194. 2(c)(ii)4 marks· CAPE Physics Unit 2 · 2016 · Paper 2On the grid provided in Figure 4, plot a graph of V_o versus R_x^{-1} and draw the best straight line through the points.
  195. 2(d)2 marks· CAPE Physics Unit 2 · 2016 · Paper 2Use your graph to determine the value of R_x which results in zero output voltage.
  196. Q181 mark · multiple choice· CAPE Physics Unit 2 · 2017 · Paper 1Item 18 refers to the following diagram. [Inverting amplifier circuit with input resistor R_i, feedback resistor R_f, and non-inverting input grounded] The gain of this amplifier is given by
  197. Q191 mark · multiple choice· CAPE Physics Unit 2 · 2017 · Paper 1Items 19-20 refer to the following op-amp voltage comparator. [Diagram of an op-amp comparator supplied by \pm 9\text{ V}, with inputs V_1 at inverting terminal and V_2 at non-inverting terminal] The supply…
  198. Q201 mark · multiple choice· CAPE Physics Unit 2 · 2017 · Paper 1Items 19-20 refer to the following op-amp voltage comparator. [Diagram of an op-amp comparator supplied by \pm 9\text{ V}, with inputs V_1 at inverting terminal and V_2 at non-inverting terminal] If the input…
  199. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2017 · Paper 1Item 23 refers to the following diagram which shows two inverting operational amplifiers connected together. [Diagram showing cascaded inverting op-amps: stage 1 with 10\text{ k}\Omega input and 50\text{ k}\Omega…
  200. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2017 · Paper 1What is the effect of negative feedback on the gain and bandwidth of an inverting amplifier?
  201. Q261 mark · multiple choice· CAPE Physics Unit 2 · 2017 · Paper 1Item 26 refers to the following diagram of an amplifier circuit. [Circuit diagram of an op-amp comparator driving an LED, with reference voltage V_1 at inverting input and LDR potential divider voltage V_2 at…
  202. 2(a)(i)1 mark· CAPE Physics Unit 2 · 2017 · Paper 2Identify the type of op-amp circuit shown in Figure 2.
  203. 2(a)(ii)1 mark· CAPE Physics Unit 2 · 2017 · Paper 2State the equation for the closed loop gain, A_CL (V_out / V_in), of the circuit.
  204. 2(b)(i)4 marks· CAPE Physics Unit 2 · 2017 · Paper 2Complete Columns 3, 4, and 5 of Table 2, given that A_OL is the open-loop gain of the amplifier.
  205. 2(b)(ii)4 marks· CAPE Physics Unit 2 · 2017 · Paper 2On the grid provided in Figure 3, plot a graph of log₁₀ A_OL versus log₁₀ f, and draw a smooth curve through the points.
  206. 2(b)(iii)5 marks· CAPE Physics Unit 2 · 2017 · Paper 2From the graph, determine the frequency response curve and hence find the bandwidth of the circuit when R_2 = 100 kΩ and R_1 = 330 Ω.
  207. Q181 mark · multiple choice· CAPE Physics Unit 2 · 2018 · Paper 1Which of the following circuits is NOT a non-inverting amplifier?
  208. Q211 mark · multiple choice· CAPE Physics Unit 2 · 2018 · Paper 1Which of the following are properties of an ideal operational amplifier? I. Zero output impedance II. Infinite input impedance III. Infinite open loop gain
  209. Q221 mark · multiple choice· CAPE Physics Unit 2 · 2018 · Paper 1For an input of 0.3\text{ V}, the circuit above will have an output of
  210. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2018 · Paper 1The open loop gain of an op-amp is very high; however, its bandwidth is narrow. This means that the
  211. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2018 · Paper 1Given that V_{\text{in}} = 6\ \mu\text{V}, what is the output, V_{\text{out}}, of the cascaded amplifiers?
  212. Q251 mark · multiple choice· CAPE Physics Unit 2 · 2018 · Paper 1What would be the output, V_0, given that V_1 = V_3 = 1\text{ V}, and V_2 = 0?
  213. 5(a)6 marks· CAPE Physics Unit 2 · 2018 · Paper 2State THREE differences between the properties of an ideal operational amplifier and a real operational amplifier, giving typical values for EACH property stated.
  214. 5(b)(i)3 marks· CAPE Physics Unit 2 · 2018 · Paper 2Sketch and label all the important features of ONE period of the output waveform when the amplitude Vₐ = 0.2 V.
  215. 5(b)(ii)4 marks· CAPE Physics Unit 2 · 2018 · Paper 2Sketch and label all the important features of ONE period of the output waveform when the amplitude Vₐ = 2.0 V.
  216. 5(c)2 marks· CAPE Physics Unit 2 · 2018 · Paper 2State the value of the voltage at Pin 2 in Figure 6 on page 22. Give ONE reason why it has this value.
  217. Q191 mark · multiple choice· CAPE Physics Unit 2 · 2019 · Paper 1Item 19 refers to the following op-amp voltage comparator. The supply voltage to the op-amp is \pm 9\text{ V}. If the open loop gain is 10^5, and V_2 = 0, what is the maximum input voltage swing, V_1, for…
  218. Q201 mark · multiple choice· CAPE Physics Unit 2 · 2019 · Paper 1The sinusoidal alternating voltage shown in Diagram 2 is applied to the input of the operational amplifier shown in Diagram 1. The voltage of the power supply is \pm 15\text{ V}. Which of the following graphs…
  219. Q211 mark · multiple choice· CAPE Physics Unit 2 · 2019 · Paper 1Item 21 refers to the following diagram where V_1 and V_2 are input signals. What are the possible values of R_1, R_2 and R_3 if the output voltage V_{\text{out}} = -(3V_1 + 4V_2)?
  220. Q231 mark · multiple choice· CAPE Physics Unit 2 · 2019 · Paper 1Which of the following graphs BEST represents the open loop gain frequency response of a real operational amplifier?
  221. Q241 mark · multiple choice· CAPE Physics Unit 2 · 2019 · Paper 1Item 24 refers to the following diagram which shows an amplifier. The values for the resistors may be changed. Which of the following pairs of values for R_1 and R_2 would give the amplifier the LARGEST bandwidth?
  222. Q261 mark · multiple choice· CAPE Physics Unit 2 · 2019 · Paper 1Item 26 refers to the following circuit diagram. What is the output voltage, V_{\text{out}}, of the op-amp in terms of V_1, V_2 and V_3?
  223. 2(a)6 marks· Physics · Unit 2 Q2 2(a)State THREE major properties of an ideal operational amplifier and explain how EACH property manifests itself when the operational amplifier is placed in a circuit.
  224. 2(a)(i)1 mark· Physics · Unit 2 Q2 2(a)(i)Write an equation to show the relationship between the output voltage, V_out, and the inputs, V1 and V2.
  225. 2(a)(ii)3 marks· Physics · Unit 2 Q2 2(a)(ii)Using the equation in (a) (i), briefly explain how a comparator works.
  226. 2(a)(iii)2 marks· Physics · Unit 2 Q2 2(a)(iii)The amplifier in Figure 3 on page 10, has a gain, A = 10^6, and is powered by a supply voltage, V_s, of ± 5 V. Determine the differential input voltage, ΔV, that will result in saturation with a negative voltage on the…
  227. 2(b)8 marks· Physics · Unit 2 Q2 2(b)Explain how the circuit in Figure 4 will function to trigger the alarm if the temperature drops below the threshold value.
  228. 2(b)(i)2 marks· Physics · Unit 2 Q2 2(b)(i)Draw a diagram of a non-inverting operational amplifier circuit, labelling all important currents and voltages.
  229. 2(b)(ii)2 marks· Physics · Unit 2 Q2 2(b)(ii)Use your diagram in (b) (i) to derive the relationship between input voltage and output voltage for the non-inverting operational amplifier circuit.
  230. 2(b)(iii)2 marks· Physics · Unit 2 Q2 2(b)(iii)A non-inverting operational amplifier circuit has a gain of 11. Suggest practical values for the resistors in your circuit in (b) (i) which will achieve this gain.
  231. 2(b)(iv)3 marks· Physics · Unit 2 Q2 2(b)(iv)On the diagram in Figure 4, sketch the output waveform, labelling the maximum and minimum points.
  232. 2(b)(v)2 marks· Physics · Unit 2 Q2 2(b)(v)State the values of the output at t = 2 ms and t = 14 ms.
  233. 2(c)8 marks· Physics · Unit 2 Q2 2(c)Determine the overall voltage gain of the circuit.
  234. 2(c)(i)8 marks· Physics · Unit 2 Q2 2(c)(i)Consider the case where a digital 1 is represented by 1 V and a digital 0 by 0 V. Complete Table 2 for the input-output characteristics of a 3-bit D/A converter.
  235. 2(c)(ii)4 marks· Physics · Unit 2 Q2 2(c)(ii)Calculate values for the resistors in Figure 5 such that the input-output characteristics of Table 2 would be realized.
  236. 2(c)(iii)1 mark· Physics · Unit 2 Q2 2(c)(iii)State the MAJOR disadvantage of the circuit in Figure 5 when used as a D/A converter.
  237. 2(d)6 marks· Physics · Unit 2 Q2 2(d)Complete the table below by inserting THREE characteristics of an ideal operational amplifier and a real operational amplifier. For EACH characteristic, state the associated values for an ideal operational amplifier and…
  238. 2(d)1 mark· Physics · Unit 2 Q2 2(d)State what is meant by the 'bandwidth of an operational amplifier'.
  239. 2(e)(i)4 marks· Physics · Unit 2 Q2 2(e)(i)On Figure 6, insert EACH of the following labels: f_c and f_u. State the numerical value of the frequency at EACH point on the graph. Cut-off frequency, f_c Unity-gain frequency, f_u
  240. 2(e)(i)2 marks· Physics · Unit 2 Q2 2(e)(i)Calculate the voltage gain of the circuit in Figure 5.
  241. 2(e)(ii)2 marks· Physics · Unit 2 Q2 2(e)(ii)Determine the value of the output voltage when the input voltage is 2 V.
  242. 2(e)(ii)3 marks· Physics · Unit 2 Q2 2(e)(ii)Determine the gain of the amplifier at 1 kHz.
  243. 2(e)(iii)2 marks· Physics · Unit 2 Q2 2(e)(iii)If the input voltage is now 5 V, state the value of the output voltage, giving a reason for your response.

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