isolation transformer - Page 1
Forum section: electronics / beginners

author: ginnmd
author_rank: Newbie
timestamp: May 20, 2014, 01:07:28 pm
content: could someone suggest what isolation transformer could be used between a function generator and test circuits to avoid grounding problems with oscilloscope? there seems to be so many different ones in Mouser, I cant decide which is ideal. I would appreciate a part # if possible so I could get the "right" one. Thanks. Im new here and I know this has probably been discussed before, but I couldn't find it under search. I apologize in advance. thanks. tg

author: madires
author_rank: Super Contributor
timestamp: May 20, 2014, 01:23:09 pm
content: Quote from: ginnmd on May 20, 2014, 01:07:28 pmAre you asking about an isolation transformer to power your test circuits or about a signal transformer to get an isolated signal input?

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 20, 2014, 01:25:10 pm
content: Do you mean mains power isolation, or signal isolation?Why do you think your signal generator needs isolation? Is it damaged?What are you trying to do that you need such unusual isolation?

author: ginnmd
author_rank: Newbie
timestamp: May 20, 2014, 01:55:14 pm
content: I mean signal isolation. sig generator is not damaged. I was told by others that some probs I had with the oscilloscope measurements could be due to grounding ( between the generator and neative probe of dso ) that could be obviated by using the isolation transformer. thanks

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 20, 2014, 02:25:26 pm
content: To select an isolation solution, you need to know what the signal is: Voltage? Current? Frequency? Impedance? AC? DC?However, I seriously question the starting premise that you NEED an isolation transformer at all.Without any more information about what you are trying to do, it is not possible to verify that you even need isolation.

author: ginnmd
author_rank: Newbie
timestamp: May 20, 2014, 02:46:51 pm
content: OK, maybe I have some other problem. I'll do a little extra work on it and repost if problem. thanks. tg

author: pinyoro
author_rank: Contributor
timestamp: June 12, 2014, 08:52:08 pm
content: You would buy an isolation transformer that is able to support the load connected to it. I bought a 3kVA one on ebay which is probably an overkill :-DDf or £25.00. I use it when working on switch mode power supplies but could be used on high power amplifiers during fault diagnosis. Just make sure it is suitable for voltage and frequency. An isolation transformer is basically a transformer with a 1:1 ratio and provides electrical isolation from the source.

author: Rory
author_rank: Frequent Contributor
timestamp: June 13, 2014, 01:46:28 am
content: I do a lot of work with 600 ohm balanced audio, so I built an isolation transformer box with BNC, RCA and 3.5mm stereo TRS unbalanced inputs, with insulated binding posts on the isolated side.

author: Jeroen3
author_rank: Super Contributor
timestamp: June 13, 2014, 05:31:32 am
content: Quote from: ginnmd on May 20, 2014, 01:07:28 pmBoth oscilliscope and fucntion gen have mains earth as gnd.You can either isolate your test circuit, or your tools. But "between" your circuit and tools is probably very expensive.