What device can convert AC to DC?

The device that can convert AC (alternating current) to DC (direct current) is a diode. A diode is a semiconductor device that allows current to flow in one direction only, making it ideal for converting AC to DC. When an AC signal is applied, the diode conducts during the positive half-cycle of the AC waveform and blocks current during the negative half-cycle. This results in a pulsating DC output.

Other options do not perform this specific function. A transistor is used for amplification and switching but does not inherently convert AC to DC. A capacitor is primarily used for energy storage and filtering but does not convert current types; while it can smooth out the pulsations in half-wave or full-wave rectification, it does not perform the conversion on its own. An inductor is used for energy storage in a magnetic field and is often involved in filtering or timing circuits but does not serve the purpose of converting AC to DC either.