You are supposed to apply a voltage to R10 instead of connecting it to 0V. Then the opamp will raise its output offset voltage.
You also do not need to make the opamp have differential inputs using 4 resistors.

 

You are supposed to apply a voltage to R10 instead of connecting it to 0V. Then the opamp will raise its output offset voltage.
You also do not need to make the opamp have differential inputs using 4 resistors.

The voltage in R10 not zero it equals to 9v

 

Since your signal source is probably at 0VDC, R9 and R10 have equal values making a voltage divider and the opamp has a gain of 1 then there is a DC offset voltage:

 

Hello,

@Audioguru again



Bertus

 

At the size that was posted, it looked like a ZERO.

 

Since your signal source is probably at 0VDC, R9 and R10 have equal values making a voltage divider and the opamp has a gain of 1 then there is a DC offset voltage:

So, you mean that put R10&R9 as the same value?
Also, put the voltage in R10 as 5v not 9v?

 

You can make the resistors any value you want depending on the amount of opamp input bias current. They make an attenuator of the AC signal and of the offset voltage you add to them.
I showed equal resistor values and an input offset of +5V so that the output of the opamp can be an average DC of +2.5V and swing from 0V to +5V without damaging a microcontroller powered from +5V.

 

You can make the resistors any value you want depending on the amount of opamp input bias current. They make an attenuator of the AC signal and of the offset voltage you add to them.
I showed equal resistor values and an input offset of +5V so that the output of the opamp can be an average DC of +2.5V and swing from 0V to +5V without damaging a microcontroller powered from +5V.

So, if I put equal resistor and 5v offset voltage I get +2.5 average dc?

 

So, if I put equal resistor and 5v offset voltage I get +2.5 average dc?

Yes, the arithmatic is simple.
But the resistors also cut the input signal level in half and the opamp gain is only 1.

 

i put resistors and offset voltage as in attachment , but also there isn't any offset occurred.

 

The settings on your scope are AC coupled, which would remove DC
offset when displayed on scope. You need to be DC coupled on the
scope inputs.


Regards, Dana.

 

The settings on your scope are AC coupled, which would remove DC
offset when displayed on scope. You need to be DC coupled on the
scope inputs.


Regards, Dana.

Okay can you tell me from where can I adjust this setting (as a screen shot for example).

 

It's right there on the upper right of each channel.

 

Okay can you tell me from where can I adjust this setting (as a screen shot for example).

Circled in red:

 

Your new resistors have the extremely low value of only 1k which might be a short circuit to your signal source.
Since you are biasing the input of the opamp at a positive voltage and the input of the opamp never goes negative, then you do not heed the negative supply. Connect pin 2 of the opamp to ground (0V).

 

Your new resistors have the extremely low value of only 1k which might be a short circuit to your signal source.
Since you are biasing the input of the opamp at a positive voltage and the input of the opamp never goes negative, then you do not heed the negative supply. Connect pin 2 of the opamp to ground (0V).

Yes, it work well thank you.
Finally can you tell me the calculation if I need to MN ake the signal +/-0.420v to has dc offset 0.420v to make the signal finally from 0 to 0.840 v

 

Your circuit began attenuating the signal with a differential amplifier. Now you want offset plus a gain of 2?

 

Your circuit began attenuating the signal with a differential amplifier. Now you want offset plus a gain of 2?

The triangular signal has magnitude from _0.420 to +0.420
So, I want all of this signal in positive only. So, I want dc offset equals 0.420 to make the signal finally from 0 to. 0.840.

 

Is your input signal AC only? What is its frequency response?
An AC signal is very simple to add a DC offset and have non-inverting gain.

 

Is your input signal AC only? What is its frequency response?
An AC signal is very simple to add a DC offset and have non-inverting gain.

Yes, my signal is ac only with 10 khz. So what should I do?