Pico 2204A shows wrong voltage

Having problems ? let us know the details here
Post Reply
Alexey22F
User
User
Posts: 2
Joined: Fri Jun 21, 2024 12:42 am

Pico 2204A shows wrong voltage

Post by Alexey22F »

Hey, I'm new scope user have a issue with my 2204A. I see wrong voltage when I'm testing 12v car electrical systems. It shows ~.5 volts less than any other voltmeters. I ordered another 2204 but it`s doing the same. I use Picoscope 7 software. Pls help :cry:
Thank you!

bennog
Advanced User
Advanced User
Posts: 216
Joined: Mon Nov 26, 2012 9:16 am
Location: Netherlands

Re: Pico 2204A shows wrong voltage

Post by bennog »

please show a photo of your measurement setup
you probably forgot to put the clip from the probe to the negative part of the battery.

Benno

Alexey22F
User
User
Posts: 2
Joined: Fri Jun 21, 2024 12:42 am

Re: Pico 2204A shows wrong voltage

Post by Alexey22F »

Thank you for quick response!
I ckeched battery voltage with 2 different multimeters. They all show ~12.2v. I reinstalled software also
Thank you, Benno
Attachments
20240621_075652.jpg
20240621_075700.jpg
20240621_075852.jpg
20240621_080016.jpg

bennog
Advanced User
Advanced User
Posts: 216
Joined: Mon Nov 26, 2012 9:16 am
Location: Netherlands

Re: Pico 2204A shows wrong voltage

Post by bennog »

and when the inputs are closed do you measure 0V or something else

the 0.5V can be an offset or something or the scope is out of calibration.
Also be aware that at +/- 20V (40V swing) a 8 bit scope will have 0.15V per bit so you are only 3 out of 250 off in this case that is slightly above 1% toleration.

Benno

Martyn
Site Admin
Site Admin
Posts: 4549
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

Re: Pico 2204A shows wrong voltage

Post by Martyn »

Do you get the same issue if you use the supplied blue USB cable?
Martyn
Technical Support Manager

G-son
User
User
Posts: 8
Joined: Wed May 05, 2021 4:11 pm

Re: Pico 2204A shows wrong voltage

Post by G-son »

I had a similar issue some time ago, sometimes it showed correct voltage, other times considerably lower.
Turns out the laptop had a bad USB port, if I remember it right the negative power had a bad connection. The scope showed correct voltages when it got the full 5V from the USB, and the incorrect voltages came when it only was fed around 2.8V due to the bad port. I'm surprised the scope worked at all at just over half the proper voltage.

Post Reply