(a)[3]
State three characteristics of an ideal op-amp.
(b)
A comparator circuit using an ideal op-amp is shown in Fig. 9.1.
(b(i))
In one use of the comparator, $V_2$ is held constant at $+1.5\,\text{V}$. The variation of potential $V_1$ with time $t$ is shown in Fig. 9.2. The potential $V_2$ is also shown.
(b(ii))[3]
Two light-emitting diodes (LEDs) R and G are linked to the op-amp output in Fig. 9.1 so that R is lit for a longer time than G. On Fig. 9.1, add the symbols for the two diodes connected to the op-amp output and label them R and G.