Amplify current

I have a pressure sensor. It generates 0.5 Vdc to 5 Vdc. I need to amplify the current from 1 ma to 10 ma. I use 2N3904 transistor. I have 9 Vdc as Vcc. I am confused about the resisters. What should be the values of them?

If you have a voltage output sensor and you need additional drive current, use an opamp in a buffer configuration (gain = 1):
http://www.eecs.tufts.edu/~dsculley/tutorial/opamps/opamps5.html

Since your voltage signal does not go down to ground, you can use a single supply opamp , a rail-to-rail part would be ideal and with a 9v power supply there are lots to choose from.

If this is a precision application you might need to choose an opamp with minimal input offset voltage or one where you can externally compensate for offset. Given your description I don't think this will be an issue.

Has Dean's reply answered your question, if not, please give more details about what it is you hope to achieve,
cheers,
Richard

Thank you for your suggestion. It worked for me.

What is Amplify-current?

I also want to know more details - i have almost the same problem with amplify current...

Olly Moros
"http://www.vocean.co.uk/about.html(Electronic Engineering Comapny)":http://www.vocean.co.uk/about.html

It should be 10mA

What kind of details do you want?