In Noninverting Amplifier, the op-amp parameters are given as follows:
A = 200,000, Zin = 1MΩ and Zout=100Ω.
Calculate the amplifier output impedance (with negative feedback)
r1 = 10kΩ
r2 = 10kΩ
The output impedance of the noninverting amplifier with negative feedback is given by the formula:
Zout = Zin/(1+AB)
where A is the open-loop gain of the op-amp, B is the voltage divider ratio of the feedback network (r2/(r1+r2)), and Zin is the input impedance of the op-amp.
Substituting the given values, we get:
Zout = 1MΩ/(1+200,000×(10kΩ/(10kΩ+10kΩ)))
Zout = 454.55 Ω
Therefore, the output impedance of the noninverting amplifier with negative feedback is approximately 454.55 Ω.
To calculate the amplifier output impedance (with negative feedback), we need to first calculate the gain of the noninverting amplifier, and then use it to determine the output impedance.
Step 1: Calculate the gain (Av) of the noninverting amplifier.
The gain of a noninverting amplifier is given by the formula:
Av = 1 + (r2 / r1)
Given that r1 = 10kΩ and r2 = 10kΩ, we can substitute these values into the formula:
Av = 1 + (10kΩ / 10kΩ)
= 1 + 1
= 2
So, the gain (Av) of the noninverting amplifier is 2.
Step 2: Calculate the amplifier output impedance (Zout).
The formula to calculate the amplifier output impedance is:
Zout = Zout_actual / Av
Given that the op-amp parameters are A = 200,000, Zin = 1MΩ, and Zout = 100Ω, we can calculate the actual output impedance (Zout_actual) as follows:
Zout_actual = Zout / (1 + (A / Av))
Substituting the given values:
Zout_actual = 100Ω / (1 + (200,000 / 2))
= 100Ω / (1 + 100,000)
= 100Ω / 100,001
= 0.0009999Ω
Finally, we can calculate the amplifier output impedance (Zout) using the gain (Av):
Zout = Zout_actual / Av
= 0.0009999Ω / 2
= 0.00049995Ω
Therefore, the amplifier output impedance (with negative feedback) is approximately 0.00049995Ω.