opamp advice

[scsn]

Hi,
Wondering if someone can let me know if this is okay?

I have an opamp which simply gets a 0-5v input and amplifies it to 0-12v, well it can be anything from 0-12v to 0-12.5v depending on other components.

I have placed a vaiable resistor (see attachment) so I can scale it up to the required voltage. It works fine on prototype board, and wondering if temperature changes am I right in thinking that the voltage will be the same as the ratio in the variable resistor wipers will always be equal?

Many Thanks
Scott

 

[ericgibbs]

hi,
A non inverting OPA will have a Gain of G= 1+[ Rf/Ri] so with an input of +5V and the pot set half way, you will get +10Vout.

I would not worry about the temperature problems regarding the pot.

If it is critical, I could run a LTSpice simulation over the expected temperature range.??

 

[scsn]

Hi Eric,
Thanks for the reply.

If you can run the simulator, that would be much appreciated, thanks

Scott

 

[ericgibbs]

Hi Eric,
Thanks for the reply.

If you can run the simulator, that would be much appreciated, thanks

Scott

hi,
Ok, give me 10 mins..

 

[ericgibbs]

hi,
This is a couple of Sims using generic components, I would not expect a big change.

 

[scsn]

Hi Eric,
Thats great, thanks for doing that, much appreciated

Scott