eli5 what is this iconic high pitched sound you hear, when a movie or game character activates night vision goggles? Is this a real thing?

Question

eli5 what is this iconic high pitched sound you hear, when a movie or game character activates night vision goggles? Is this a real thing?

In: Technology

Answer 1

early analog night vision devices used a vacuum-tube type video display to amplify the signal. This was the days before LCDs were everywhere. Pure analog amplification of light. The tubes required high voltage to run, so the sounds you are hearing are the capacitors charging that run the amplification tubes. Yes, they made that sound, kinda. But only the older ones. New ones don’t anymore, they are all digital and use LCD displays.