Current to voltage converter

[Tojatomek]

current to voltage converter opamp

Hi I'm looking for scheme of current to voltage converter that convert current 0-100µA to 0 to 5V. I tried with OpAmp, but it didn't work, maybe I made something wrong.

 

[Vamsi Mocherla]

resistance to voltage converter

Put your OPamp in transimpedance amplifier mode, i.e., the current will see the input terminals and there is a resistance on the feedback which will give you a V = I*R

 

[Tojatomek]

current to voltage converter using op amp+pdf

You mean something like this on picture?
If so can you tell me what opamp should be, because I tried with LT1058(quad) and it don't works

Ps. R should be 50kΩ ?

 

[VVV]

current to voltage converter using op amp

You need to power the opamp with a negative source, too. That is because the output will go negative when the current flows "into" the input.


The resistor should be indeed 50kΩ. The calculation is simple: Imax*R=Vmax.

Generally any opamp will work. Of course, there are other issues: offset, bias currents, accuracy (due to gain), etc. But the circuit will work.

 

[Tojatomek]

current-to-voltage converter op-amp

Will something like this work?
Of course this is not a real thing, just example

 

[Vamsi Mocherla]

lm3914 car ammeter

Well, if you maintain the the opamp in its bias conditions, it should not be a problem at all. Your current source hence should also have good output impedance.

 

[VVV]

current to voltage converter with opamp

So you need a photodiode amplifier...
Check this out: www.national.com/an/AN/AN-1244.pdf#page=1
www.national.com/appbriefs/files/AppBrief104.pdf#page=1

Or just go to National, Knowledge base and search for photodiode.

 

[Tojatomek]

logarithmic current-to-voltage converter op amp

Thanks. I actually build a ammeter to my application(not this on upper picture) that will show value on 10 LED by Lm3914. So I need this converter.
If I need range 0-100µA I what OpAmp conditions mast be done?
I add part of my application scheme
1-original version
2-what i'm going to do
Will it work?

 

[VVV]

current to voltage converter photodiode

I don't think it will, since your input is always with respect to ground and the circuit needs a "floating" meter.
I suggest you use a resistor instead of the meter (that will enable the orifginal circuit to works as it was intended) and build a differentiaal amplifier with one or-two opamps and measure the voltage across that resistor.

 

[Tojatomek]

photodiode current to voltage converter

Can you draw me it, I don’t understand everything because of my bad English. Thanks...

That is differential amplifier?

 

[blue2lucy]

My suggestion is to check the application notes. There's a great deal of information there.

 

[yuiko]

you can use very simple circuit of inverting op

 

[Tojatomek]

I'm not good electrician, can you exactly tell what you mean. Thank you.