So i want to use my oscilloscope on this device that has a two wire step down transformer. Would it be fine as long as i connect the alligator clip of the probe to the ground of the circuit?
thanks

 

I'm sorry, but the crystal ball is a little fuzzy and I can't seem to see the device you are refering to. Maybe a photo or schematic would make it clearer

 

It's not a particular device... I was wondering if since there is a two wire transformer on its power supply it would be ok. I did some research on the topic but couldn't come to a conclusion.
thanks

 

It's not a particular device... I was wondering if since there is a two wire transformer on its power supply it would be ok. I did some research on the topic but couldn't come to a conclusion.
thanks

Ok but your reference to "This device" led me to believe it was something specific
Take a look at the files below from Tektronics..

 

If the device has galvanic (isolation transformer) isolation then you should be OK as long as no reference to earth ground, which also depends on the practice at your location (country of Orig.)
Max.

 

Yeah that's what i thought. I tested a step down transformer i had laying around and since there is no connection between the windings i don't see why i can't probe inside the circuit. When i tested a three wire power supply there was low impedance from the ground wire to the positive pin of the output, and therefore shouldn't be probed with an oscilloscope when live. Correct?

 

How did you measure 'Low impedance'?
If the circuit is isolated from the supply then there should be no problem using a 'scope.
Max.

 

The simplest test is to connect a low wattage INCANDECENT domestic light bulb light bulb from your supply Earth and touch the other end to the secondary outputs of the transformer. If it lights up or trips your consumer unit rcd, = not safe. If not, then should be O.K.
Do not just test with a meter as you will have some capacitive coupling that will give a misleading reading on the meter!

 

Did the light bulb test and it didn't light up.. thanks a lot guys, your inputs cleared my confusion

 

You can always do this to check every time before you connect the scope earth to anything.

 

So i want to use my oscilloscope on this device that has a two wire step down transformer. Would it be fine as long as i connect the alligator clip of the probe to the ground of the circuit?
thanks

some "old hands" lifted the earth wire from the mains plug - but a lot of them didn't live to become actually old.

 

So i want to use my oscilloscope on this device that has a two wire step down transformer. Would it be fine as long as i connect the alligator clip of the probe to the ground of the circuit?
thanks

Depending on type/brand of scope frequency and voltage to measure.
Hard to give information without the DUT ( device under test) type/model scope and what you expect to measure.( goal of that exercise)
Scope signal gnd could produce a ground loop or shortcut or act as an antennae messing up the results.

Picbuster

 

The most simplest solution for galvanic separating is to use the autonomous USB oscilloscope fed by batteries. Just three AAA and voila!
I mean such like an Harbin Intrustar QDso based on AD9288 input and RA8872 graphics. The 40 MHz is the max max. Yet I would be more satisfied if it had a two channel, but there is single. But is is the only solution when I need to look anything on 330 000 Volt wire on electron microscope cathode, without of alternatives. The price at ebay was something about 100 USD.

If the Voltage to be separated off is little bit more brainful, like under the kilovolt, I use the picoscope what is up to GHz and has 4 channels but demands the laptop. However laptop may be operated on batteries, but if something goes wrong, I risk with 7500 for picoscope and at least 500 for laptop. Better to risk with the 100 "moneys". So, when the voltage is not so big, I use the simple insulation trafo, what is wound by myself on the first core what was at shelf nearer to me.