У вашего броузера проблема в совместимости с HTML5
This is a 3½ digit panel voltmeter circuit using ICL7107 IC. Its voltage range is 20V. But you can change it to 200mV, 2V, 20V and 200V. TL431 use as external reference and ICL7660 as voltage converter.
For more information: http://www.electronicecircuits.com/electronic-circuits/icl7107-panel-meter