Help with Resistance?

Question

With no load resistor across the output terminals of the amplifier, and Vin = 0.25 V, the output voltage, Vout = 5 V. With a resistor of 50 Ω across the output terminals, Vout = 2 V. What is the output resistance of the op-amp?

Thanks in advance!

Answer 1

I just can't resist that!

Voltage divider (and never mind the input voltage).

Vout = Vin (Rl /(Rout +Rl)

Vin = 5V (no load output)
Vout = 2 V ( with 50 Ω load)

Rout= (Vin / Vout - 1) Rl
Rout= (5/2 -1) 50=75 Ω