Have you noticed you can "feel" if a house has no power?.....So a spot light of mine needed recharging, i plugged it in and a very high pitch noise came from the wall plug. Normally when it is left plugged in, i do not notice a sound coming from it. I am wondering just how many electronic items are emitting sounds that we may not acknowledge. Sounds not within our hearing range can still be detected by the body ....long term that could add alot of stress.
Has any one else noticed there electronic devices emitting odd sounds?