very good day, I hope to channel the problem well by this means. the problem in question is the following I have a source of 12v and 5v and -12v the problem in question was that measuring the voltage of 12 and -12v gives me 17 and -17. My question is this voltage can be true or is it a misleading measure. For example, this medicine can damage the rest of the circuit. How can I know if this measure is true by taking a resistance if the load does not fall. Thank you for your attention and advice.