Transformer question need help!

[northernmach]

I am trying to use this tranformer at the following link. http://www.alliedelec.com/Images/Pro...TIC/F-401U.pdf

When I conect to the primary and then test at the secondary wires shouldn't it be in vdc? I still show vac. I am very confused and don't want to go to the capacitor with it. I lost the instructions that were for one of hobbycnc's boards.

Thanks,
Chad

[erase42]

no the output will always be AC when coming thru a transformer, the device that will convert it to DC for you is a rectifier. Usually a full wave bridge rectifier is what is used. It is made up of 4 diodes but you can usually find in the form of one unit with 4 leads. The AC goes in to two of the leads and DC magically flies out the other two leads. Do

[erase42]

oops. Do a google search for bridge rectifier and im sure you will find the info you need.

Ed

[northernmach]

thanks for the help erase! That will definately clear things up for me.

[Madclicker]

Originally Posted by erase42 no the output will always be AC when coming thru a transformer, the device that will convert it to DC for you is a rectifier. Usually a full wave bridge rectifier is what is used. It is made up of 4 diodes but you can usually find in the form of one unit with 4 leads. The AC goes in to two of the leads and DC magically flies out the other two leads. Do

Just spitting hairs, but the output of the bridge is also AC, but with a DC content. The cap stores much of the AC peak voltage and supplies a relatively clean DC.

[erase42]

this is true, but when you really back up and look at it, does the transformer even exsist?

[Madclicker]

Originally Posted by erase42 this is true, but when you really back up and look at it, does the transformer even exsist?

Yes.

[Al_The_Man]

Originally Posted by Madclicker Just spitting hairs, but the output of the bridge is also AC, but with a DC content. The cap stores much of the AC peak voltage and supplies a relatively clean DC.

Alternating means it changes polarity, the bridge output does not, it is pulsating DC, 120hz ripple from peak to zero.
Al.

[erase42]

wasnt sure if the pulses could be considered alternating, thought not, but life is too short to go around standing up for things you are merely pretty sure of. the original gentleman got his answer so he could move on tho, hopefully thats the ultimate purpose of these forums.

[Madclicker]

Originally Posted by Al_The_Man Alternating means it changes polarity, the bridge output does not, it is pulsating DC, 120hz ripple from peak to zero. Al.

Alternating just means it changes from one low value to another higher value. The current alternates from zero at the bottom to whatever the peak is in the case of the output of a rectifier bridge. Alternating signals are all characterized also by their DC content. If this were not true, the measured AC value of the output of the bridge would be 0? But, it never is.

[Al_The_Man]

The output of the transformer alternates polarity 60 times a sec, the bridge rectifier 'Steers' this and produces a pulsating DC. i.e. the Bridge output does not 'Alternate' polarity, as the transformer output (and Primary supply) does.
If it did not alternate, there would be no need for the Bridge.
Al.

[Madclicker]

Originally Posted by Al_The_Man The output of the transformer alternates polarity 60 times a sec, the bridge rectifier 'Steers' this and produces a pulsating DC. i.e. the Bridge output does not 'Alternate' polarity, as the transformer output (and Primary supply) does. If it did not alternate, there would be no need for the Bridge. Al.

The current AND the the voltage alternate. ALTERNATING CURRENT. NOT ALTERNATING POLARITY. Alternating as in "changing"!