Help on this simple circuit- OP AMP output

[JoaoJzn]

Hello all .
I'm having trouble on interpreting this operational amp connections. ( it's on the bottom right ).

I'm trying to connect this way: IN(-) is the jumper from port 4 of the DAC. IN(+) is GND , and VCC+ is +12V.
But this way is not working. I'm kinda new on this circuit area and i'm not sure how do i connect this right . Following this image can someone help me how do i do the right connections?

*The idea of the circuit is: get the small current from the DAC , and amplify it to give the correct voltage to the Proportional Valve ( the input signal to the DAC comes from an Arduino )

Thanks !!!

 

[davenn]

OK it's connected in an inverting mode
what pins of the Op-Amp do you have power connected to ?

 

[JoaoJzn]

OK it's connected in an inverting mode
what pins of the Op-Amp do you have power connected to ?

im using an UA747. I tried to connect in many ways , right now i was testing with:

Port IN- of the AMP: is the I0 out of the DAC , (small current from the DAC to be ampl)
Port IN+ of the AMP i was using the GND ,
Port VCC of the AMP +12V from my power source

but seems to be not working.

thanks

 

[davenn]

im using an UA747. I tried to connect in many ways , right now i was testing with:

Port IN- of the AMP: is the I0 out of the DAC , (small current from the DAC to be ampl)
Port IN+ of the AMP i was using the GND ,
Port VCC of the AMP +12V from my power source

but seems to be not working.

thanks

ok but you still didn't quite answer my Q .. so for the 747 what pins did you connect power to ?
VCC and ?
and are you only using a single rail PSU ? they generally work better with a split rail supply but start with a single rail supply and see how it affects the signal

Did you REALLY want an inverting configuration ?


Dave

 

[JoaoJzn]

ok but you still didn't quite answer my Q .. so for the 747 what pins did you connect power to ?
VCC and ?
and are you only using a single rail PSU ? they generally work better with a split rail supply but start with a single rail supply and see how it affects the signal

Did you REALLY want an inverting configuration ?


Dave

Hi Dave thanks for Helping ,
I'm kinda newbie on this
But I'm connecting power only on the VCC port (+12V) , is that correct ?( I don't know if the schematic that I'm following is missing some information about this power supply)
I want this configuration to amplifiy the current from the DAC to be used on a proportional valve . I'm just reproducing this circuit , is part of a tutorial that I'm reproducing to study about pneumatic systems .

 

[davenn]

But I'm connecting power only on the VCC port (+12V) , is that correct ?( I don't know if the schematic that I'm following is missing some information about this power supply)

you need a split rail PSU as the DAC IC and the Op-amp both need it so that is a PSU that has +12V, 0V and -12V
+ 12V going to pin 13 Vcc + of the Op-amp and pin 14 of the DAC via that 5k1 resistor
-12V Pin 4 Vcc- of the Op-amp and pin 3 of the DAC
0V to anything that is showing the ground symbol around the circuit eg pin 2 of the DAC and pin 2 of the Op-amp

till you get your missing power rails sorted out, it isn't going to work

 

[JoaoJzn]

you need a split rail PSU as the DAC IC and the Op-amp both need it so that is a PSU that has +12V, 0V and -12V
+ 12V going to pin 13 Vcc + of the Op-amp and pin 14 of the DAC via that 5k1 resistor
-12V Pin 4 Vcc- of the Op-amp and pin 3 of the DAC
0V to anything that is showing the ground symbol around the circuit eg pin 2 of the DAC and pin 2 of the Op-amp

till you get your missing power rails sorted out, it isn't going to work

Perfect , Thanks for helping and being patient !!!
I'm connecting my psu to a breadboard . One side i have +5V and 0V . on the other side i have 12V and -12V. I'm connecting all the grounds together.
I will connect the OP-amp this way you said now .
Thanks again!

 

[davenn]

OK just make sure you double check your wiring before powering up and hopefully you wont
let the magic smoke out

keep us informed

 

[JoaoJzn]

OK just make sure you double check your wiring before powering up and hopefully you wont
let the magic smoke out

keep us informed

I'm going to the lab tomorrow and i will make some tests. The idea is to change a digital value on the arduino code , and the voltage output on the OP amp changes according to my digital value on the arduino code.