- #36
gneill
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Electric potential difference is measured between two points. That's why it's called a "difference". An isolated transformer secondary has an effectively undefined potential with respect to anything else. What is defined is the potential difference between its leads.kiki_danc said:Oh before it forgot. I want to understand more this phenomenon of floating secondary output of isolated transformer. Say a 240v-120v step down isolation transformer produced 120v output. And one of its leads is not connected to ground. What are the situations when the voltage can rise above 120v? Like 1000V. Is it not the output will always be 120v? But if you let the neutral or one of the leads touch say 1000v.. the output can become 1120v? how? by series? How does this work when output is supposed to be 120v but the actual is 1120v? how is the 1120v measured? between the load (but it should be 120v).. hence the confusion.
When you connect a lead of the secondary to something with an established potential (with respect to what? Ground?), then you elevate the whole secondary by that potential. Note that there will still be 120 V between the two leads. That doesn't change.