Q $2($c$)[6$ Marks$]$ A two input cumulative timer is used in which one input acts as an enable switch and the other acts as the timer input. Thus the timer can be interrupted and the timer will remember and keep a running total of the time elapsed while the timer input is on$.$ Every time the enable input is switched off, the output goes low and the timer is re$-$ zeroed and is ready for restart whenever the enable input is turned back on$.$ Construct a response characteristic to describe the operating characteristic of this timer with a $3$ second delay.

Q $2($d$)[7$ Marks$]$ Design a system using the timer in Q$2$c which will give a signal when a process continues to run after it has been operating for a period of $3$ seconds. The $3$ second period can be made up of shorter intervals of time. After the $3$ seconds if the process is switched off, the signal from the system should switch off as well.