$1)$ Design a lithium battery pack overheating protection circuit which senses the temperature of a $7\mathrm{.}4$V lithium battery pack $($which consists of two $3\mathrm{.}7$V batteries in series$)$ and disconnects it from the load which it's powering if the pack gets too hot, and reconnects it again when it cools. You should use a thermistor and any commercially available op$-$amps, comparators, FETs, BJTs$,$ Zener $($your choice of voltage$)$ and other types of diodes, resistors and any capacitors or inductors you need. The thermistor has a resistance of greater than $\backslash (10\backslash$mathrm$\{$k$\}\backslash$Omega $\backslash )$ when the battery is cool and reduces to below $\backslash (9\backslash$mathrm$\{$k$\}\backslash$Omega $\backslash )$ when too hot; your circuit should disconnect when the resistance decreases to below $\backslash (9\backslash$mathrm$\{$k$\}\backslash$Omega $\backslash )$ and reconnect when the resistance increases again to above $\backslash (10\backslash$mathrm$\{$k$\}\backslash$Omega $\backslash ).$ Your circuit should operate from the voltages available from the two series$-$connected batteries in the pack $($and you have access to the terminal between the two series$-$connected batteries$).$ For highest credit on this problem give manufacturer part numbers for all semiconductors $($such as are given in the Analog Devices parts kit$).$