An ideal op-amp in negative feedback obeys which two 'golden rules' due to Sedra-Smith?
AV+ + V- = Vcc; output is V_out = Vcc/2 always
BOutput is always 0 V; input draws infinite current
CNo current flows into inputs; V+ ≈ V- (virtual short)
DInput bias current is finite; offset voltage is large
Answer & Solution
Correct answer: C. No current flows into inputs; V+ ≈ V- (virtual short)
Ideal op-amp with negative feedback: infinite gain forces V+≈V-, and infinite input impedance gives I_in≈0. These two rules solve nearly all linear op-amp circuits.
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