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6 marksOperational Amplifiers

CAPE Physics Unit 2 · 2004 · Paper 2 · Question 6(c)

The non-inverting amplifier circuit shown in Figure 6b is designed to adjust gain from 20 to 50 by rheostat R_s, with R_i = 1 kΩ.

Determine the value of R_f and the range of the rheostat R_s.

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Other parts of this question

  1. 6(a)(i)Show that the closed loop voltage gain, A, in the circuit is given by A = 1 + R_f / R_i.[4 marks]
  2. 6(a)(ii)Explain how the circuit differs from that of an inverting amplifier circuit.[2 marks]
  3. 6(a)(iii)State what the input impedance of the non-inverting amplifier is.[2 marks]
  4. 6(b)The 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…[2 marks]
  5. 6(d)Design 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…[4 marks]

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