(a)[2]
State, with reference to the input and output signals, the function of a non-inverting amplifier.
(b(i))[1]
Fig. 7.1 shows the microphone-and-amplifier circuit. The output potential difference $V_{\text{OUT}}$ is $2.6\,\text{V}$ when the potential at point $P$ is $84\,\text{mV}$. Find the gain of the amplifier circuit.
(b(ii))[2]
Find the resistance of resistor $R$.
(c(i))[1]
For the circuit in Fig. 7.1, suggest a suitable device to attach to the output so that the shape of the waveform of the sound picked up by the microphone can be examined.
(c(ii))[2]
For the circuit in Fig. 7.1, state and explain what happens to the output potential difference $V_{\text{OUT}}$ if the resistance of resistor $R$ is increased.