a$)$ Explain what you understand by a load line in BJT circuits including descriptions of the extreme points.

$[25\%]$

b$)$ Draw the collector curves for a BJT and indicate various operating regions for the BJT$.$ Explain various operating regions for the BJT$.[30\%]$

c$)$ Draw gain versus frequency curve for a discrete circuit BJT amplifier. Explain why gain falls of at low and high frequency bands.

$[20\%]$

d$)$ For the circuit of Figure Q$3$d$,$ find $v_{E_1}{v}_{C_1}$ and $v_{C2}.$ Assume that $|v_{BE}|$ of a conducting transistor is approximately $0\mathrm{.}7$ V and that common$-$base current gain, $$~~$1.$