[SOLVED] how to convert analog output voltage (3V to 5V and 4.6V to 5V) to (0V to 5V)

[maxima_diesel]

Hi I just wanted to convert the output voltage of the circuit I have made to a wider range of 0V to 5V. I would need this output to be analog, so the output shouldnt be 0V. OR 5V. I have two circuits, the first one's output range is 4.6V to 5V and the second has a range of 3V to 5V. How would you change those output to 0V to 5V?. Thanks a lot in advance.

 

[betwixt]

The easiest way is to use a comparator.
Set the 'comparison' voltage somewhere close to the middle of the input voltages and the output will swing from one logic level to the other (typically 0 to 5V) as the input exceeds it.

Brian.

 

[alexan_e]

I don't he is asking for that, he wants an analog result with all the values between.

I would need this output to be analog, so the output shouldnt be 0V. OR 5V.

Alex

 

[maxima_diesel]

The easiest way is to use a comparator.
Set the 'comparison' voltage somewhere close to the middle of the input voltages and the output will swing from one logic level to the other (typically 0 to 5V) as the input exceeds it.

Brian.

Hi Brian,
Thanks for the reply, Im just wondering if using a comparator setup like u described would have the analog voltage output that I would want, so the range is 0V to 5V instead of an output of (logic low)0V and (logic high)5V? Do you have any other suggestions? thanks in advance.

 

[Tahmid]

You would need a DC level shifter. Have you searched on this?

I think you can implement it with an opamp.

Hope this helps.
Tahmid.

 

[maxima_diesel]

You would need a DC level shifter. Have you searched on this?

I think you can implement it with an opamp.

Hope this helps.
Tahmid.

Thank you very much for your reply Tahmid. Do I implement a DC level shifter using a difference amplifier? Is it ok if you can elaborate on what sort of op amp setup i should be using/looking for?

thanks a lot again.

 

[mister_rf]

You may try to use a summing amplifier circuit based upon the standard Inverting Operational Amplifier configuration that can be used for combining multiple inputs. See the example:

 

[maxima_diesel]

You may try to use a summing amplifier circuit based upon the standard Inverting Operational Amplifier configuration that can be used for combining multiple inputs. See the example:

Thanks for reply mister_rf, I don't think youve posted the example correctly is it ok if u can post it again so I can look at it? thanks again

---------- Post added at 13:04 ---------- Previous post was at 12:52 ----------

You may try to use a summing amplifier circuit based upon the standard Inverting Operational Amplifier configuration that can be used for combining multiple inputs. See the example:

Thanks for reply mister_rf, I don't think youve posted the example correctly is it ok if u can post it again so I can look at it? thanks again

 

[mister_rf]

In practice need also to use some buffer to obtain Vref.

 

[maxima_diesel]

thanks sir, I shall try it, may i ask what sort of program/software/webiste did u use to create the schematic u just shown me?? i would also like to to try it for the other setup: 3V to 5V converted to 0V to 5V. thank you very much for your assistance

 

[mister_rf]

It’s a very small program, TINA Design Suite,
**broken link removed**
but you can use any simulation software you like…

To solve the problem need to put data into the summing amplifier equation:

V out = V2* (R2+R1)R4/R1(R3+R4) – V1* R2/R1

For the thanks you may use 'helped me' button... :lol:

 

[dselec]

google it .."op amp circuits" or
**broken link removed**
generally all u need is a ref volt like mister.. post and use fixed resistors with rotary switch to get several fixed outputs .

**broken link removed**
install ltspice and u can run any-circuit and get real time scope like voltages

 

[maxima_diesel]

It’s a very small program, TINA Design Suite,
**broken link removed**
but you can use any simulation software you like…

To solve the problem need to put data into the summing amplifier equation:

V out = V2* (R2+R1)R4/R1(R3+R4) – V1* R2/R1

For the thanks you may use 'helped me' button... :lol:

cool thanks, atm I cannot seem to download the demo because I am at uni, is it ok for you to change the input voltage range from 3.5V to 5V and the output from 0V to 5V? and post the schematic here? thanks in advance.. sorry for being a pin and sorry i didnt know there is a help button here.. :S

 

[mister_rf]

Summing amplifier equation:

Vout = V2* (R2+R1)R4/R1(R3+R4) - V1* R2/R1

we replace
R2/R1 = x
and
R3/R4 = y

For the new conditions:


Vout = 0V for V2 in = 3V
0 = 3* (x+1)/(y+1) - V1* x

and
Vout = 5V for V2 in= 5V
5 = 5* (x+1)/(y+1) - V1* x

simplifying equations:

5 = 5* (x+1)/(y+1) - 3* (x+1)/(y+1)
5 = 2 (x+1)/(y+1)
5(y+1)= 2(x+1)

x= (5y +3) / 2

if we chose
y= 1
solution:
x= 4
and
V1= 3(4+1) / 4(1+1)= 15/8= 1.875V