A heat dissipation device includes a mounting plate for mounting the heat dissipation device to a circuit board on which a CPU and a plurality of capacitors are mounted, a heat sink, a core, and a fan mounted on the heat sink. The vent baffle assembly includes a first vent sheet and a second vent sheet. In an internal space of the case, a circuit element such as a semiconductor element is housed. The circuit further includes a mixer and buffer circuit operable to output a reference voltage including a sum of the first and second voltages.