11.1 : 理想二极管

An ideal diode is a nonlinear circuit element with the anode as its positive terminal and the cathode as its negative terminal.

When a negative voltage is applied, no current flows. This is called reverse bias or cut-off, where the diode acts as an open circuit.

If a positive voltage is applied, the diode behaves as a short circuit with zero voltage drop. This state is called forward-biased or being turned on.

The ideal diode exhibits piecewise linear I-V characteristics with two straight-line segments at 90 degrees to each other.

Unlike ideal diodes, practical diodes exhibit a small forward-biased voltage drop and a non-zero reverse-biased leakage current.

The ideal diode used in rectifier circuits converts AC into DC. During the positive half-cycles of the input sinusoid, the diode conducts, and the output voltage equals the input voltage.

During negative half-cycles, the diode does not conduct, resulting in zero output voltage.

So, the rectified output voltage is unidirectional and has a finite average value or a DC component.