# circuit to mesure ac voltage

1. ## circuit to mesure ac voltage

Hello everyone,

I am doing this circuit.

Here is the result I got,

However, in reality I could not get this signal.i don't know why
PS: I got the AC voltage by circuit a voltage divider.

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2. ## Re: circuit to mesure ac voltage

So show us the exact "reality" circuit you used.
What AC and DC voltage sources do you have?

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3. ## Re: circuit to mesure ac voltage

Superposition theorem
The superposition theorem for electrical circuits states that for a linear system the response in any branch of a bilateral linear circuit having more than one independent source equals the algebraic sum of the responses caused by each independent source acting alone, where all the other independent sources are replaced by their internal impedances.

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4. ## Re: circuit to mesure ac voltage

ac =1.5 V

dc =1.5 V
here is the schema in complis that I wanted to achieve

however at the beginning I wanted to buy the op amp.

i tested the circuit with out amp op i jsute tested the input but i don't find what i need find

5. ## Re: circuit to mesure ac voltage

Hi,

Please focus on the "non working curcuit".
It makes no sense to show the "working" circuit, but complaining another circuit.
--> photo, exact schematic, exact components and wiring

And please give unambigous informations.
ac =1.5 V
In technical discussions we mainly use the RMS value.
In opposite to this in mathematical discussion one often uses the "amplitude value"

With sine value:
1V RMS = 1.414Vp (peak) = 1.414V ampltude = 2.828Vpp (peak-to-peak)
= 1.414V × sin(wt)

Btw: the simplest solution I see is just a capacitor and a resistor:
AC --- C --- (output) --- R --- 1.5VDC.

But there are several ways, with and without Opamp, with and without capacitor...
You first have to decide your requirements / specifications.

Generally: if the real results differ a lot from the expected results, then - most probably - you are doing something wrong.

Klaus

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6. ## Re: circuit to mesure ac voltage

Coupling capacitor or transformer required for mixing AC signal + DC

for example

7. ## Re: circuit to mesure ac voltage

thanks for the informations so if i understood you i must use a capacitor with the ac input

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