Electronics > Beginners

Viewing Generator Output With an Oscilloscope

(1/2) > >>

tvl:
Remove

basinstreetdesign:
I have used low voltage (120Vac - 6.3Vac) power step down transformers as audio output transformers in small amplifiers.  Testing them has taught me that they make pretty good wide BW transformers.  They will respond from below 50 Hz to beyond 40 KHz and are pretty linear.  As long as you do not saturate the core of the transformer then the output should show a pretty good rendition of the waveshape of the 120V source.  And the isolation provided, alone, makes it worth trying.

David Hess:

--- Quote from: tvl on January 02, 2019, 03:40:18 am ---My question is as follows: Whether the generator output be a PURE & CLEAN sinewave OR be DISTORTED & DIRTY, will the use of a step down transformer still provide me a true "picture" of the generator output quality OR will the transformer mask or make things appear differently …………… whether it be for the better or for the worse?
--- End quote ---

The sine wave is not very distorted but has residual high frequency noise from the inverter function.  Monitoring it through a small power transformer will work fine.

soldar:
IMHO, if what you want to see is the actual waveshape then I would avoid a transformer because by introducing it you are introducing all sorts of unknowns. I think there is a much easier way.

Your scope has one of the leads grounded to earth (or you can ground it). Right?

You generator has one side of the output grounded (or you can ground it) . Right?

So you already have a common reference. Now you have 120 V rms on the generator's live wire and you do not want to stick the scope probe in there directly. Well, you can use two resistors to make a voltage divider and bring it down to a lower voltage.

My 'scope has a x10 (1:10) dividing probe.

Zero999:

--- Quote from: soldar on January 02, 2019, 03:37:20 pm ---IMHO, if what you want to see is the actual waveshape then I would avoid a transformer because by introducing it you are introducing all sorts of unknowns. I think there is a much easier way.

Your scope has one of the leads grounded to earth (or you can ground it). Right?

You generator has one side of the output grounded (or you can ground it) . Right?

So you already have a common reference. Now you have 120 V rms on the generator's live wire and you do not want to stick the scope probe in there directly. Well, you can use two resistors to make a voltage divider and bring it down to a lower voltage.

My 'scope has a x10 (1:10) dividing probe.

--- End quote ---
Only connect the x10 probe to the live wire. Don't connect the oscilloscope's chassis to the neutral or there's a risk a large current could flow through it, as the neutral voltage will be a bit higher than the earth voltage.

Navigation

[0] Message Index

[#] Next page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod