Electricity in Switzerland is 230 V, 50 Hz AC. Plug sockets are round and take three round pins (types C and J) - they can take europlugs with two pins. If you are coming from the US, UK or Ireland, as well as from many other countries, you will need an adaptor. Travellers from the US (and other countries with a different voltage than 230 V) additionally need a voltage converter. In modern hotels you might find multi-use sockets. Otherwise ask for an adaptor / converter at the reception or buy one in a traveller's or electronics shop.