An ideal operational amplifier (op-amp) is assumed to have infinite open-loop gain and infinite input resistance (impedance). State three additional properties of an ideal op-amp.
Fig. 10.1 shows a circuit that detects temperature changes.
At a thermistor temperature of $1.0^\circ\text{C}$, the voltmeter shows $+1.0\,\text{V}$. Show that, when the thermistor is at $1.0^\circ\text{C}$, the potential at A is $-0.20\,\text{V}$.
The potential at A stays at $-0.20\,\text{V}$. Work out the voltmeter reading when the thermistor temperature is $15^\circ\text{C}$.
At a thermistor temperature of $29^\circ\text{C}$, the voltmeter reading is $0.35\,\text{V}$.
Assuming the voltmeter reading varies linearly with temperature across the range $1^\circ\text{C}$ to $29^\circ\text{C}$, calculate the reading at $15^\circ\text{C}$.
Suggest why the answers in (b)(ii) and (c)(i) do not agree.