I have this circuit:
And I am asked to find the driving point impedance.
I know that a driving-point impedance relates the voltage and current at a pair of terminals. The formula for the driving-point impedance is:
$$ Z(s)=\frac{V(s)}{I(s)} $$
But how do I calculate the driving point impedance for this circuit? Is it just transforming $$ C_{1} + R_{1} $$ to the s-domain, so that the driving point impedance is:
$$ Z(s)=R_{1}+\frac{1}{C_{1}s} $$
Or am I missing something?
The input impedance you've calculated is correct.
For an ideal op amp, you can treat the input impedance of the \$v^-\$ as infinite.
So in that case, your calculation is correct.
If this is a second year college class, or even a third year college class but the start of it, then they probably mean an ideal op-amp. If they said it's an ideal op-amp, then it's an ideal op-amp.
If they've given you a whole bunch of information on the op-amp itself, then that might be relevant to the input impedance not being exactly infinite. Basically, you do not have to worry unless the frequency that you are working at is approaching the bandwidth of the op-amp circuit.
