Small signal transformer for step down Mains.

Thread Starter

AlexLPD

Joined Aug 22, 2010
60
Hi, sorry for the long time not posting the work has been demanding.
I make a teste yesterday, and I have two things they are not quite in line:

I make the "capacitor, inductor frequency divider", as first test, the idea is to test the most of you kind filters, post in here, some I cant do for the moment due the lack of the right components. (so hold steady =)

So, this is the diagram, the parts and the reactance values calculated for 60Hz and 50Khz (60Hz from Mains AC line and 50Khz for the signal carrier.

Diagram and values
Inductor Measurement
Capacitor measurement
Circuit under test
Some measurements on the scope.

In the measurements on the scope I have some weird problems... I can read correctly the mains, I have to turn the X10 of the probe, and the peak to peak measurements are far off. I check the line voltage measuring with my multimeter I got 131VAC RMS.

I test the lead of the scope on the signal generator of the scope, they turn ok, 10Khz at 5Vp.
What Im doing wrong ?
I double check before connect the scope to the AC line, and I use the Non contact voltage of my multi meter to check for the neutral wire, to be used as "ground".

In a differente comment, Mr. Dick Cappels signal I got some distortion of my sine wave due the harmonics on my transformer, in a very interesting matter, if I plug the Oscope to the Mains, I got the same distortion (see the picture above please), near the peak on the left side, what could be causing this on my grid?

This filter is non effective, since I can clearly see a 60Hz AC signal, so I will move to the next test.

In a interesting commend I search the power line communication chip posted above, and some comment on the store say the manuffacture has declared obsolete, changue the version to a TDA 5051A.

Here is the datasheet TDA5051A, and got some examples transform and transformerless for the RX and TX signal, even to 250VAC.

I will make a more detailed post on this.

I got some ideas form Ron and Danko, so I will give them a try.
Thanks for the insights.
 

DickCappels

Joined Aug 21, 2008
7,424
In a differente comment, Mr. Dick Cappels signal I got some distortion of my sine wave due the harmonics on my transformer, in a very interesting matter, if I plug the Oscope to the Mains, I got the same distortion (see the picture above please), near the peak on the left side, what could be causing this on my grid?
Probably other people's transformers and possibly the distribution transformer on the pole.
 
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