Let’s think we have two 24V power supply. These power supplies doesnt have connection to earth and each other. How much voltage would I see if I measure voltage difference between ‘+’ of first power supply and ‘-‘ of second one ? Once I tried it and I saw something like 7-8V but I didn’t think it was a logical value. I mean I shouldn’t see any value but because of structure of digital multimeter I saw some pointless value but then my collegue told me that we can measure a value and As he said if we measure 15V and if we placed a lamp operating with 15V between ‘+’ of first ps and ‘-‘ of second ps the lamp will flash.
Is that correct ? If yes , why there is a voltage difference since there is no referance to each other ?
Is that correct ? If yes , why there is a voltage difference since there is no referance to each other ?