How do i connect this V-I converter up

[riie]

Hi all,

I need to have an AC current source for testing but i do not have any equipment that can generate an AC current source. I have a function generator to produce an AC sine voltage and thinking to convert V to I using the transconductance op amp.

The first stage of my test circuit consists of an tranimpedance amplifier with other stages at the back and how can i connect current output of V to I(Left Side) and input of I to V (Right side)? (Ciruit as attached)

Is there any other suggestion for the conversion of the AC voltage source to AC current souce from function generator?

 

[FvM]

 

[riie]

Thank you!

Seem to work for simulation.
Now onto the actual implementation.

 

[riie]

I have my simulation set up as attached.
But having problem if the voltage input peak amplitude is less than 1V.

The attachment show a Vpeak 0.01V AC sine wave. Does anyone knows what is causing the offset?

 

[FvM]

The models have a built-in offset voltage, representing the expectable range for the chosen OP type. Actual offset can have positive or negative polarity. If it's too high for your application, use different resistor dimensions (lower transconductance/higher input voltage) or refer to low offset OPs.

 

[riie]

U mention that use different resistor dimensions refers to higher resistance values?
I want to output an AC sine current with peak of uA.

Sorry if I had asked stupid question.

 

[FvM]

If I understand right, you got all results up to now in simulations. It's a perfect tool to try out different resistance levels and V/I conversion factors to find a suitable solution for your application.