I am assuming they are looking for something R1 = R2, R3 = R4, as the question only asks for input resistance, not asks for R_Vin_1 and R_Vin_2.The V_in_2 input resistance is 10k. What about V_in_1?
I am lost, can you tell me a bit more?If V_in_1 and V_in_2 are two independent sources, then the input resistances in your schematic are NOT equal.
If you have a single voltage source connected across the inputs, the input resistance is STILL not 10k.
The question in the OP is word by word from our exercise, I am not sure, but from what I understand it, is the resistance to the ground.So - do you require the resistance as "seen" by an input signal source connected between the differential input terminals to be 10kΩ?
I mean the resistance see by the inputs, not the resistance between the inputs, but I don't think I truly understand the question, I will need some help.What do you mean by "resistance to ground". You suggest this is your understanding of the wording. How do you know this is what was meant by the wording?
I got R2+R1||R4, is that what you expected?OK - so let's say we connect V_in_2 directly to ground and connect a non-zero ground referenced input to V_in_1. What is the input resistance on each input?
We have talk about input impedance (of differential amplifier) in class, I am guessing the tutor want us to look the info up.This is the circuit (attached) I would draw in response to that question.
With two voltage sources, there are two input resistances.
Arrrh, are you trying to guild me to R_in_1 = R2+R1||R4, and R_in_2 = 0?OK - so let's say we connect V_in_2 directly to ground and connect a non-zero ground referenced input to V_in_1. What is the input resistance on each input?
This is homework. What do you think, and why?We have talk about input impedance (of differential amplifier) in class, I am guessing the tutor want us to look the info up.
but good to know there are two input resistances with two voltage source.
so do you consider a high side current sensing circuit as one voltage source?
more to google: differential mode and common mode input resistanceSince the context is differential amplifier I would tend to make a distinction (if any) between differential mode and common mode input resistance.
Ooops, I suppose to type "we HAVE NOT talked about this in class"This is homework. What do you think, and why?