# Vol 3, Ch3: Clamper Circuits First Figure Issue

#### DukeGranite

Joined Jan 13, 2013
2
In the first figure (a) and (b) show the same circuit except for the diode placement. The text mentions "Suppose the polarity of the diode is reversed as in Figure above (b)" but it's not shown that way in the figure because the capacitor and source are also reversed.

I discovered that when I made the circuits as shown in the figure and didn't get the expected results. Then I remembered the section about rectifiers and realized the issue.

#### Georacer

Joined Nov 25, 2009
5,182
An AC source doesn't have polarity, as opposed to a DC one. A capacitor is also a linear passive component, so it doesn't have polarity either. What these mean is that you cannot change the polarity of an AC source (not taking phase into account) and a capacitor.

The only thing that is different between figures (a) and (b) is indeed the polarity of the diode in respect to the ground node (0).
In figure (a) the diode allows only negative charge to be held at its anode. In other words the anode must be more negative than the cathode in order to hold charge (diode is cut off).

In figure (b) the diode allows only positive charge to be held at its cathode. In other words the cathode must be more positive than the anode in order to hold charge (diode is cut off).

Is that clear?