What device is used to convert AC into pulsating DC?

The device that is used to convert alternating current (AC) into pulsating direct current (DC) is a rectifier. Rectifiers utilize components such as diodes to allow current to flow only in one direction, effectively transforming the bidirectional flow of AC into a unidirectional flow, resulting in pulsating DC.

When AC voltage is applied, the rectifier enables only the positive portion (or negative portion, depending on the design) of the wave to pass through while blocking the other half. This process changes the shape of the waveform, creating a pulsating output that varies in voltage over time. Although this output is not pure DC, it can be smoothed further using filters like capacitors and inductors to produce a more stable DC voltage.

Other devices mentioned have different functions. For example, a transistor acts as a switch or amplifier in electronic circuits, and a capacitor stores electrical energy. An inductor, on the other hand, stores energy in a magnetic field when current flows through it. Each of these components plays an essential role in electronic devices, but they do not specifically perform the function of converting AC to pulsating DC like a rectifier does. Thus, the rectifier is the appropriate choice for this conversion process.