У вашего броузера проблема в совместимости с HTML5
https://howtomechatronics.com/how-it-works/electrical-engineering/schmitt-trigger/ ► Find more details here. The Schmitt Trigger is a logic input type that provides hysteresis or two different threshold voltage levels for rising and falling edge. This is useful because it can avoid the errors when we have noisy input signals from which we want to get square wave signals. Visit HowToMechatronics.com for more Tutorials, Tips, Projects and How It Works videos: ► https://howtomechatronics.com/ Like my page on Facebook: ► https://www.facebook.com/howtomechatronics Add me on Google+: ►https://plus.google.com/+Howtomechatronics Music: Aduro by Jens Kiilstofte (machinimasound.com/music)