An exemplary stand (60) includes a housing (610), an adjustable base (68), a pulley (630), a sleeve (635), a rotating member (636), a resilient member (632), a sliding member (62), and a cable. The adjustable base is fixed to one end of the housing. The adjustable base has a driving component (681), a follower (682), and a rotation shaft (683). The driving component is configured to rotate the follower. The rotation shaft is fixed to the follower. The pulley is rotatably connected to the housing. The sleeve is slidably disposed on the housing, and engages the rotation shaft. The rotating member is rotatably received in the sleeve. The resilient member is fixed to the adjustable base. The cable partially coils around the pulley, and connects the resilient member to the rotating member. A sliding member is slidably connected to the housing and fixed to the cable.