A power supply is hardware that converts incoming electrical energy into the voltage and current a device or circuit needs. It may be a fixed adapter, a bench supply, a battery system, or a negotiated source such as USB-C Power Delivery. In practice, the power supply is not just “plugs and watts”: it determines whether a device boots, resets, brownouts, or behaves erratically under load.
In cyber security, power supplies matter because unstable or malicious power can disrupt hardware, hide faults, or reveal secrets through side channels. Defenders use controlled supplies to test devices under known conditions, while attackers may exploit poor power quality, oversupply, or timing changes to crash systems, force recovery modes, or observe power signatures. When analyzing modern embedded or USB-C setups, checking the power supply is a basic step in confirming that the device is receiving the expected power profile and that any failure is not caused by the source.