did i break physics?

[neo]

i have a 17 volt transformer i soldered a bunch of thinks together, the dip sockets being outputs as this was supposed to be for a vfd tester i was building but when i went to test it with my multimeter i found 50v where there should have only been 25, anyone got any ideas? did i break physics?

[zlymex]

Multimeter problems?
High frequency interference?
Analog multimeter on AC range?

[neo]

what high frequency? i checked it 10 times against know value and 10 out of 10 my multimeter was accurate and i dont have an analog multimeter

[Rerouter]

I havent looked at the PDF, but i experienced something similar before, a 18V transformer, measured 18V AC, but when i rectified it, measured 42V DC, had to pull out the scope to figure it out, turns out the transformer was somewhat resonant with the RFI filter caps i had used, and was spiking up to 45 volt but only for a very short period.

[neo]

ill test it on my oscilloscope but my multimeter wasnt flying all over the place it was rather solid value but i don't know if that means much

[helius]

Some of you may enjoy this lecture on the topic of "breaking physics":



See if you can spot what he does "wrong".

[timgiles]

As with all those on Youtube that claim similar, if you consider that all the scientists at CERN, spending billions of Euros, manage to 'break physics' only a few times over 15-20 years of planned operation, I doubt if you have managed it with a single capacitor!

[ZeTeX]

Then your transformer might supply more then 17V with no load.
this is an easy test, wire up your transformer to the mains, connect it and then measure AC voltage using your multimeter.
if a transformer is sold as 12V it might supply 13V or 17V no load, because they spec 12V on it at load.

[neo]

Then your transformer might supply more then 17V with no load.
this is an easy test, wire up your transformer to the mains, connect it and then measure AC voltage using your multimeter.
if a transformer is sold as 12V it might supply 13V or 17V no load, because they spec 12V on it at load.

its used and it was thoroughly tested to be 17 volts and you never know stranger things HAVE happened it might be 1 in a trillion for all i know but i do doubt it or i wouldnt be asking here, here is my theory i think somehow it is in series with itself or perhaps as suggesting resonating

[Rick Law]

...
...
 did i break physics?

Damn!  It was you!  I was wondering why gravity is not working for me, and I thought it was what I was smoking.

[neo]

...
...
 did i break physics?

Damn!  It was you!  I was wondering why gravity is not working for me, and I thought it was what I was smoking.

this is without a doubt the funniest joke iv'e heard all year.

[mikeselectricstuff]

Transformers are usually specified at full load. For a cheap, small transformer, the off-load voltage can easily approach 2x the full-load voltage, especially when you also consider variation in mains voltage.

[ZeTeX]

Then your transformer might supply more then 17V with no load.
this is an easy test, wire up your transformer to the mains, connect it and then measure AC voltage using your multimeter.
if a transformer is sold as 12V it might supply 13V or 17V no load, because they spec 12V on it at load.

its used and it was thoroughly tested to be 17 volts and you never know stranger things HAVE happened it might be 1 in a trillion for all i know but i do doubt it or i wouldnt be asking here, here is my theory i think somehow it is in series with itself or perhaps as suggesting resonating

Maybe somehow the transformer spikes to an higher voltage and the capacitor just holds the peak, ofcourse with even a small load this will drop.
what is the W\VA of your transformer?

[Fungus]

i have a 17 volt transformer i soldered a bunch of thinks together, the dip sockets being outputs as this was supposed to be for a vfd tester i was building but when i went to test it with my multimeter i found 50v where there should have only been 25, anyone got any ideas? did i break physics?

Depends on what you mean by "transformer".

If it's one of those old copper-wire&iron things then there's no mystery, you've just rediscovered 'inductance'. Put a load on the output and it will drop down.

[Ian.M]

First I'd want to check the multimeter - a fresh 9V alkaline should read between about 9V and 9.3V on its DC volts ranges, and on its AC V ranges, assuming its CAT II or better, the mains supply (measured via a lead fused at no more than 3A - for your safety, firmly connected to your test probes so you don't have to touch or hold any part of the wiring with the power on), should read within 10% of 120V. If its NOT CAT II or better rated don't attempt to check your mains supply voltage.

TLDR: Before claiming physics is broken, sanity check your instrumentation! 

[neo]

 maybe it is inductance, as for the mention of sanity checking my equipment i crosschecked it 10 times

[Ian.M]

Photo please, so we can see the s--t you are actually testing and see how you have it hooked up.   What's the measured AC voltage across the ends of the secondary and what's the make and model of your meter?

[max_torque]

Have you soldered TWO output windings in series by an chance??

Ie dual tap output, both of 25V, in series you get 50V!

[neo]

no because this is the only one though that was my first thought

[ZeTeX]

no because this is the only one though that was my first thought

OK, upload a picture of your setup, show us your transformer, show us how you measure the transformer output voltage, show us how you measure the 50V.
Don't replay unless you have pictures - this is going nowhere.

[Fungus]

maybe it is inductance, as for the mention of sanity checking my equipment i crosschecked it 10 times

If there's no load on the transformer then it's inductance. No need to look further.

Put a load on the output (eg. a 220 Ohm resistor) and watch it drop down.

[Macbeth]

This whole thread reminds me of Batteriser Batteroo doing all their battery voltage tests with no load whatsoever 

The mysterious +/-17V is from what? Without anything to go on here why even bother? 

[Audioguru]

The schematic does not show a transformer and does not show a rectifier. Instead it shows inputs of +17V and -17V feeding one 1000uF capacitor and the +17V input connects to the +50V output and the -17V input connects to the -50V output.

[Ian.M]

You think that's bad, you should see his schematics in his other topic! 

They're about as useful as a London Tube map on the Moscow Metro. 

[Audioguru]

The schematic does not show a transformer and does not show a rectifier. Instead it shows +17V and -17V inputs connected to a polarized 1000uF capacitor and the -17V input connects to the +50V output and the -17V input connects to the -50V output.