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ELEC$2346$ Homework Assignment

Due date: Nov $28,2024($before $11$:$59$ pm$)$

Scan and convert your handwritten work $($in A$4$ size paper$)$ into a single PDF file, and submit it to Moodle before the above deadline. Late submission$/$re$-$submission will not be accepted. Remember to put down your full name and $10-$digit student ID number on the first page of your work.

Question $1$

Consider the op amp circuit of Figure $1.$ Assume the op amp is ideal.

$($a$)$ Express the voltage $v_a$ in terms of the two input voltages $(v_l,v_2)$ and two input resistor values $(R_1,R_2).$

$($b$)$ Suppose $v_{\text{I}}=6V,v_2=3V,R_{\text{I}}=10k,$ and $R_2=20k.$ Find $v_a.$

$($c$)$ Express the voltage gain $G$ of the op amp circuit in terms of $R_3$ and $R_f,$ where $G=\frac{v_o}{v_a}.$

$($d$)$ Suppose $R_3=R_f=10k.$ By using the results in $($b$)$ and $($c$),$ find the output voltage $v_o.$

$($e$)$ Assume the supply voltages of the op amp are $+12$ V and $-12$ V $,$ and the input voltage $v_l$ can be adjusted freely by using a programmable DC power supply $($where $v_{l}0V)$ while the other parameters remain unchanged. Determine the maximum value of $v_l$ in such a way that the output of the op amp will not be saturated.