# How to Handle negative signal with Arduino Uno

#### musabfarooq

Joined Mar 22, 2017
38
I am currently working on a project in which I have to read 5V pk-pk analog signal with arduino uno ADC. Since Arduino Uno ADC input range is 0-5V, what should I do to read the signal with Arduino Uno ADC and recover it afterwards.

#### ericgibbs

Joined Jan 29, 2010
16,745
hi musab,
Do you have more details of the 5Vppk signal frequency etc.??
What is the source of the 5Vppk.?
E

#### ericgibbs

Joined Jan 29, 2010
16,745
hi,
Depending upon the frequency and source drive, a simple circuit like this would work.

E

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#### crutschow

Joined Mar 14, 2008
31,091

#### btebo

Joined Jul 7, 2017
100
ericgibbs,

Pretty neat. I simulated it in MultiSim and got same results - but without the 1meg resistor... With that resistor, output was 0V. What is the purpose of it?

#### musabfarooq

Joined Mar 22, 2017
38
hi musab,
Do you have more details of the 5Vppk signal frequency etc.??
What is the source of the 5Vppk.?
E
Frequency of signal is 50 Hz. Basically I am measuring current non-intrusively.

#### musabfarooq

Joined Mar 22, 2017
38
hi,
Depending upon the frequency and source drive, a simple circuit like this would work.

E
My input can vary from 0V pk-pk to 5V pk-pk. Will this circuit work for that range?

#### shteii01

Joined Feb 19, 2010
4,644
You need a dc offset to move the signal "up". The voltage divider is the easiest way to do it.

#### crutschow

Joined Mar 14, 2008
31,091
Pretty neat. I simulated it in MultiSim and got same results - but without the 1meg resistor... With that resistor, output was 0V. What is the purpose of it?
The 1meg resistor just represents the micro load.
It has no significant effect on the signal.