What device converts 120 volts AC to 12 volts DC?

The fundamental role of a DC power supply in amateur radio is to convert standard household alternating current (AC) mains voltage, such as 120V AC, into a stable direct current (DC) voltage, typically around 12V to 13.8V DC. This provides a safe and compatible power source for transceivers and accessories. An inverter performs the exact opposite function, converting DC battery power back into AC power. A power conditioner is designed to clean up and stabilize AC power but does not convert it to DC. A low-pass filter is an entirely different component used to attenuate high radio frequencies in a signal line, and it has nothing to do with converting AC mains power to DC equipment power.