You can tell from the size of the capacitors.

Gosh... and I thought they were comparing their inductors!

 

Supply for opamp and ADC would be regulated voltage (5V).
But supply to divider as i said 24V . there might be sudden changes in it. it is varying over the time.
thats why i wanted suppression and consistency on sudden changes.
my thinking is an capacitor is fare enough on divider network. any other suggestions ??

 

S

 

S

 

Don't understand why you feel that you need an op amp, just put the resistor divider into your adc chip.

 

Ok consider it is divider and ADC.
whether a capacitor on the divider is enough ??

 

Don't understand why you feel that you need an op amp, just put the resistor divider into your adc chip.

I think he has maybe read the reccomendation of using an opamp between the divider and the ADC in certain Microchip datasheets, IIRC.

 

And nobody asked if this were an AC signal or a DC signal. Also, you never specified the load. If the draw is quite low then your best bet is those resistors. And why not just get a 50KΩ pot and trim it to the desired level. Then you can dial in your accuracy and totally negate any of the percentages of error found in standard resistors.

Might also help us to know what you're building. Perhaps you're going at it all wrong. But I don't know that for sure.

 

How about a potentiometer?

 

So you have a signal that can vary from 0 to 24 volts and you're converting that to a digital signal. Putting a capacitor on the input would mess with that signal. When you change from one level to the next rather than having a clean change you'll get a floating change from one level to the next. The bigger the capacitor the longer the float from one level to the next. Your signal to digital conversion will lag seriously. I wouldn't suggest using a capacitor on the signal side (the input).

If all we're talking about is reading a signal (a voltage level) then the divider network is the best way to go. You'll get immediate responses without any lag. Using an op amp will just waste a lot of resources and will also complicate the circuitry. Simpler is better.

 

Thanks guys,

Can Any one suggest an IC for this application.
let me tell once more my application..

Input is varying voltage but DC, would be converted to digital values (by ADC) and host has to read this values.

Host whatever i'm using doesn't have Inbuilt ADC.
So have to use it externally. So someone can suggest me exact IC with everything on chip (resistor divider and ADC and may be interface to host communication (i2c or something)).

 

https://www.amazon.com/s/ref=nb_sb_...analogue+to+digital+converter+microchip&ajr=0

You'll have to find one that suits your design.