An electrical apparatus includes a casing, a circuit board, a top cover and an active heat-dissipating element. The casing includes a first entrance, a first receptacle, a first sidewall, and a first bottom surface. An air inlet hole is formed in the first bottom surface. A concave region is defined at a junction between the first sidewall and the first bottom surface. An air outlet hole is formed in the concave region. The circuit board is disposed within the first receptacle and has at least one electronic component mounted thereon. The top cover shelters the first entrance. The active heat-dissipating element is disposed within the first receptacle and arranged over the air inlet hole. Ambient air is inhaled into the first receptacle by the active heat-dissipating element and exhausted out of the casing through the air outlet hole, thereby removing heat generated from the electronic component.