Rectifier principle: Because a diode mimics an open/closed switch depending on polarity, an alternating current (AC) input can be ______ by a diode network.

Introduction / Context:
Diodes conduct current primarily in one direction. This directional behavior allows conversion of AC to pulsating DC, the first step in most power supplies before filtering and regulation. Recognizing ”rectification” distinguishes the role of diodes from regulators, attenuators, or general control elements.

Given Data / Assumptions:

• Ideal diode forward-conducts and reverse-blocks (open/closed switch analogy).
• Input is sinusoidal or any alternating waveform centered around zero.
• Load and transformer details are not required to define the action.

Concept / Approach:
Half-wave and full-wave rectifiers pass only portions of the AC cycle to the load. A single diode creates half-wave rectification; two diodes with a center-tapped transformer or a four-diode bridge produce full-wave rectification. Regulation (steady DC level) requires additional components such as capacitors, inductors, or IC regulators beyond simple diodes.

Step-by-Step Solution:

Verification / Alternative check:
Oscilloscope inspection of load voltage in a diode rectifier shows unidirectional pulses; adding a capacitor smooths these pulses toward DC, demonstrating the separation between rectification and filtering/regulation stages.

Why Other Options Are Wrong:

• Regulated: Requires active control or reference; diodes alone do not maintain a constant output level (except zeners used differently).
• Controlled/attenuated: Generic terms; the diode's primary use in this context is rectification.

Common Pitfalls:
Expecting a ”smooth DC” directly from a rectifier without filters; the immediate output is pulsating and load-dependent.

Final Answer:
rectified