voltage to current converter circuit analysis

[manjunath]

Hi all,

I am new to electronics  circuits and i know basics about the Op-Amp. I need to know how the voltage across inverting terminal changes wrt voltage change across non inverting terminal.

Please help me to analysis the attached circuit.

Thanks.

[tggzzz]

I am new to electronics  circuits and i know basics about the Op-Amp. I need to know how the voltage across inverting terminal changes wrt voltage change across non inverting terminal.

General starting principle with any opamp circuit that is operating "normally": the output does whatever is necessary to ensure that the inverting and non-inverting inputs are at the same voltage. If they aren't then the output voltage will be the (very high) open-loop gain times the voltage difference.

There are many many introductions to opamps on the web; google is your friend.

[manjunath]

ya i have gone though some basics about op amp. Here my doubt is for a voltage above 1.7V across non inverting terminal i can able to get both inverting terminal and non inverting voltage at same value (I think at this time gives high output voltage) and for a voltage level below 1.7V across non inverting terminal i am getting a voltage of 2.5V across the inverting terminal.  Why i am getting this difference ?

[Seekonk]

R3 is going to have the drive current & the transistor current. 

[T3sl4co1l]

What is the arrow at the base of R3?  That doesn't look like a Multisim standard.

Tim

[IanB]

What is the arrow at the base of R3?  That doesn't look like a Multisim standard.

It looks like the numeral 4 overlaid on top of the line?