An ideal operational amplifier (op-amp) has infinite open-loop gain and infinite input resistance (impedance). State three other properties of an ideal op-amp.
The circuit in Fig. 10.1 is designed to detect changes in temperature.
When the thermistor is at a temperature of $1.0^{\circ}\text{C}$, the voltmeter shows $+1.0\,\text{V}$. Show that, for the thermistor at $1.0^{\circ}\text{C}$, the potential at $A$ is $-0.20\,\text{V}$.
The potential at $A$ stays at $-0.20\,\text{V}$. Determine the voltmeter reading when the thermistor temperature is $15^{\circ}\text{C}$.
The voltmeter reading for a thermistor temperature of $29^{\circ}\text{C}$ is $0.35\,\text{V}$. Assuming the voltmeter reading changes linearly with temperature across the range $1^{\circ}\text{C}$ to $29^{\circ}\text{C}$, calculate the voltmeter reading at $15^{\circ}\text{C}$.
Suggest why your answers in (b)(ii) and (c)(i) are different.