# Voltage sensor and signal conditioning scheme

#### andodeki

Joined Dec 28, 2023
7
I have a Voltage sensor and signal conditioning scheme i got from here.

https://ernane-aac.github.io/RMS-Voltage-Measurement/

I have tried to reproduce it on Proteus simulation to understand how it works but i am stuck an still dont know how it works. Does it take in AC Voltage and steps down to 15V. Where does the -15V and +15V source? Where i have DC Voltage measurement at the right end of the schematic i were connectors. When i simulate its showing 0.20V on both.

Can someone assist on checking if i have captured the circuit as desired and help me figure out what i am dealing with?

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#### eetech00

Joined Jun 8, 2013
3,951
I have a Voltage sensor and signal conditioning scheme i got from here.

https://ernane-aac.github.io/RMS-Voltage-Measurement/

I have tried to reproduce it on Proteus simulation to understand how it works but i am stuck an still dont know how it works. Does it take in AC Voltage and steps down to 15V. Where does the -15V and +15V source? Where i have DC Voltage measurement at the right end of the schematic i were connectors. When i simulate its showing 0.20V on both.

Can someone assist on checking if i have captured the circuit as desired and help me figure out what i am dealing with?

#### Ian0

Joined Aug 7, 2020
9,817
The ±15V supplies are something the author assumes you already have available!
That's a mighty complicated circuit. It's perfectly possible to do it with a single 5V supply.R6=R7=2R5.
You can add capacitors to filter out high frequency if you want.

#### andodeki

Joined Dec 28, 2023
7
The ±15V supplies are something the author assumes you already have available!
That's a mighty complicated circuit. It's perfectly possible to do it with a single 5V supply.View attachment 311125R6=R7=2R5.
You can add capacitors to filter out high frequency if you want.
So instead of +15V i can use 5V so it means i can add a module HLK-PM01 to stepdown the AC voltage supply to 5V?
Also did i capture in the Proteus circuit the desired circuitry from the author

#### Ian0

Joined Aug 7, 2020
9,817
So instead of +15V i can use 5V so it means i can add a module HLK-PM01 to stepdown the AC voltage supply to 5V?
Also did i capture in the Proteus circuit the desired circuitry from the author
Yes.
Don't forget that if you are measuring the mains voltage you MUST isolated it.

#### andodeki

Joined Dec 28, 2023
7
Yes.
Don't forget that if you are measuring the mains voltage you MUST isolated it.
Now thats another thing. Isolation. I have seen and heard about it but how does that happen in actual terms?

#### Ian0

Joined Aug 7, 2020
9,817
Now thats another thing. Isolation. I have seen and heard about it but how does that happen in actual terms?
There must be physical separation between the mains and the low voltage circuitry.
It is tested by connecting a 2500V voltage source between the mains terminals of the equipment and the low voltage terminals: the insulation must not fail, no current is allowed to flow.

Measurement of AC mains is generally accomplished by using a transformer.

#### andodeki

Joined Dec 28, 2023
7
Upload just the .pdsprj file. You can zip it up if you want.
it seemed to big to upload here i dont know why but i zipped it and uploaded into google drive

#### andodeki

Joined Dec 28, 2023
7
There must be physical separation between the mains and the low voltage circuitry.
It is tested by connecting a 2500V voltage source between the mains terminals of the equipment and the low voltage terminals: the insulation must not fail, no current is allowed to flow.

Measurement of AC mains is generally accomplished by using a transformer.
A photocoupler can act as an isolation though right?

#### Ian0

Joined Aug 7, 2020
9,817
A photocoupler can act as an isolation though right?
Yes, but it isn't linear, so you won't be able to measure anything beyond an on-off measurement.

#### andodeki

Joined Dec 28, 2023
7
The ±15V supplies are something the author assumes you already have available!
That's a mighty complicated circuit. It's perfectly possible to do it with a single 5V supply.View attachment 311125R6=R7=2R5.
You can add capacitors to filter out high frequency if you want.
how does this circuit relate to the one with the author?
Or have you have just simplified it?

#### Ian0

Joined Aug 7, 2020
9,817
how does this circuit relate to the one with the author?
Or have you have just simplified it?
I simplified it. The original had three op-amps. Mine needs only one.