AC Line Noises getting through test equipment

Status
Not open for further replies.
L

lewisP

Banned
Joined
May 16, 2015
Messages
28
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Visit site
Activity points
0
What can I use to filter out all kinds of different noises and interference's coming from the AC line wall socket into the bench test equipment. If I plug my PC laptop switching power supply in the AC line wall socket, the switching will be picked up on my bench power supply and oscilloscope. I have to turn off the lights on the workshop because there is noise ,interference, high frequency spikes. I have tried EMI/RFI filters, line conditioners and used an Isolation transformer, they help some but still noisy and high frequency spikes when lights are on and if I have switching power supplies plugged into other AC wall sockets. What can I do to solve this problem?
 

lewisP said:
If I plug my PC laptop switching power supply in the AC line wall socket, the switching will be picked up on my bench power supply and oscilloscope.
Click to expand...

I had the same thing happen with my equipment.

Cable TV, audio/video components. These had no problem until I hooked up my laptop AND plugged in the AC adapter. Then 60 cycle hum came through the speakers.

I tried disconnecting this and that. The hum stopped when I unplugged either (a) incoming cable TV, or (b) laptop adapter.

In fact, I did not need to pull out the cable plug entirely. If I only pulled it out 1/8 inch, so as to disconnect the outer part (ground), the hum stopped. The center wire (signal) could stay in contact.

This made me decide the problem was a ground loop.

used an Isolation transformer
Click to expand...

I believe this would have solved my problem. I didn't try it.

If it did not help in your case, then the problem could be something else.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…