an electronic device such as an ac / dc power adapter includes a conductive heat dissipation system . the device contains heat generating components and is powered via power supply leads by an external power supply circuit . the device further contains a thermally conductive mass that is thermally coupled to both the heat generating components and to the power supply leads . when the power supply leads are coupled to receive electricity from the external power supply circuit , heat generated by the device is thermally conducted into the external power supply circuit via the power supply leads .