GW Instek Signal Generator Shows 5Vpp, Oscilloscope Reads 10Vpp—Why the Difference?

Using a brand new GW Instek signal generator into discrete components at the very beginning of a new project (not much done yet). Powering the components (transformer, resistor) with the GW Instek signal generator - both square wave and sine wave into my components shows 5vpp on the siggen but 10vpp on the oscope - nothing in the discrete components could be doubling the peak-to-peak voltage from 5vpp to 10vpp - no setting on the siggen either. Any recommendations/opinions are appreciated!

Does the input impedance of your circuit match the output impedance of the generator?
This is the most likely cause of the discrepancy.

Thank you - the XL (inductive reactance) of the primary may be too low. I'm pulsing it at 1Khz, sine wave and square wave, doesn't matter, same result, scope shows double the peak-to-peak setting of the siggen. I independently tested the oscope with a different circuit and eliminated the scope as the source of the issue.

50ohms = 2pi(1000)L, so L needs to be at least 50 / (2000pi) = 7.95 millihenries which is feasible, I think I've got at least that much XL.

This is a new siggen and I'm trying to verify it is sound/operable. A bit concerned at this point.

OK, if you're going into a transformer they can present very complex impedances. First of all, check your signal generator - feed it into a resistor as close as you can get to 50 ohms (22+18+10 will do it) and see what you get on your scope, also on the best meter you have. That will give you an idea of how accurate your sig gen output is.

If your load impedance is exactly 50 ohms (resistive) you should get the stated output of the sig gen, If it's any different (even 50 ohms inductive or capacitive) you'll get a different reading. (Do you have an impedance meter at all, or an LCR Meter?)

Finally, if you put a square wave across an inductance you will get ringing and all manner of strange effects. depending on the frequency and the inductance. Sine waves shouldn't hassle like this, though.

You can always read the input voltage using your scope and then take the output voltage, that will give you an idea of what your circuit is doing.

Good luck!!

A little more on transformers. The primary inductance with the secondary open circuit is one thing. The inductance at the primary with the secondary shorted is called the leakage inductance and will be much less. The impedance at the primary with a correct load on the secondary will be a combination of inductance and resistance - the inductance usually between the primary inductance and the leakage inductance, in parallel with the secondary resistance times (or divided by) the turns ratio. That's a simplification - transformer losses are also taken into account! So you are on very shaky ground here.... (Here be dragons, as they said on the old maps

As I read your replies today I haven't been back to my build but will follow your advice, I'm surprised I didn't think of using resistors to test the siggen. I think I was freaked out about buying new gear that was iffy.

It doesn't help that I can't directly measure inductance. I don't have inductance on my digital multimeter which is an unhappy but temporary situation - I'm looking online tonight to choose/order an LCR meter. I tried searching on Klein Tools but they seem to target electricians, not hobbyists building boards with discrete components. Thanks for the help.

Not sure where you are, sounds like the US. In which case try these:

https://www.newark.com/peak/lcr45/lcr-meter-hand-held-200khz/dp/56Y1285

https://www.newark.com/multicomp-pro/mp780402/lcr-meter-hh-20000uf-2000h-20mohm/dp/52AH6652

I don't have the Peak one but their equipment is good and nicely priced.
I do have a multicomp LCR meter simiar to the one above and it is great, really good equipment.
I hope one of those fits your budget...

Cheers