Hello all,
Today in class we were talking about the non-inverting op-amp configuration and how we would like our op-amps to have a high input resistance, without sacrificing any gain.
The circuit attached is the provided solution to this dilemma and the professor went on to talk about input resistances and output resistances of the non-inverting voltage amplifer (circuit attached) and the non-inverting current amplifier (similiar circuit).
We defined the input resistance for the voltage amplifer as simply,
\(R_{in} = \frac{v_{1}}{i_{1}}\)
Where the two are the voltage divided by the current across the first resistor, \(R_{1}\).
He then attempted to explain the output resistance of the voltage amplifier as well as the current amplifier. (non-inverting configuration)
He scribbled a few things on the board, erased them and was constantly rearranging his explanation. As a result, I'm extremly confused as to how we find the output resistance of these two circuits.
Someone care to explain?
Also, we've looked very briefly at the "inside" of the amplifier. From what we've since it's simply an resistor \(R_{in}\) connected to ground, where the voltage across said resistor (\(V_{in}\)) is the controlling voltage of a voltage controlled voltage source, \(A \cdot V_{in}\) in series with one last resistor, \(R_{out}\).
Could someone please clarify how we obtain the output resistance of each amplifier (voltage and current) and why they are important?
Thanks again!
Today in class we were talking about the non-inverting op-amp configuration and how we would like our op-amps to have a high input resistance, without sacrificing any gain.
The circuit attached is the provided solution to this dilemma and the professor went on to talk about input resistances and output resistances of the non-inverting voltage amplifer (circuit attached) and the non-inverting current amplifier (similiar circuit).
We defined the input resistance for the voltage amplifer as simply,
\(R_{in} = \frac{v_{1}}{i_{1}}\)
Where the two are the voltage divided by the current across the first resistor, \(R_{1}\).
He then attempted to explain the output resistance of the voltage amplifier as well as the current amplifier. (non-inverting configuration)
He scribbled a few things on the board, erased them and was constantly rearranging his explanation. As a result, I'm extremly confused as to how we find the output resistance of these two circuits.
Someone care to explain?
Also, we've looked very briefly at the "inside" of the amplifier. From what we've since it's simply an resistor \(R_{in}\) connected to ground, where the voltage across said resistor (\(V_{in}\)) is the controlling voltage of a voltage controlled voltage source, \(A \cdot V_{in}\) in series with one last resistor, \(R_{out}\).
Could someone please clarify how we obtain the output resistance of each amplifier (voltage and current) and why they are important?
Thanks again!
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