Daily Halacha - Is it permissible to set an alarm clock to ring on Shabbat?

Is it permissible to set an alarm clock to ring on Shabbat?

It is permissible to set, before Shabbat begins, both mechanical and electronic alarm clocks, including phone alarms. However, regarding turning them off, there is a distinction between them. A mechanical alarm clock may be turned off, but with an electronic alarm clock, although it's not clearly prohibited according to the strict law, nevertheless, if leniency is allowed in this matter, people might mistakenly permit other electrical devices as well, and therefore it should be prohibited [Yalkut Yosef p. 450].

If a cell phone rings on Shabbat, is it permissible to move it so that it doesn't disturb household members?

One should not move a cell phone, even an inexpensive one, since it is considered a utensil whose primary purpose is for prohibited activities, and moving it is not considered a permissible use for the object itself or its place. All the more so, one should not move an expensive cell phone, as it is considered muktzeh due to concern for monetary loss [Responsa of the Rishon LeZion 1, 28].

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