Circuit Cellar‘s editorial staff endeavors to publish accurate information. When mistakes are made, the staff will note them on this page and include corrections.

If you think a mistake was published in Circuit Cellar, please send your comments and suggestions to editor@circuitcellar.com.

Circuit Cellar 267 (October 2012)

A reader, Bruno Couillard, noted a few errors in equation that ran in Robert Lacoste’s October 2012 article “Introduction to IIR Filters” (Circuit Cellar 267). Couillard wrote:

I really enjoyed your latest article on IIR filters in the October issue of Circuit Cellar 2012. I really think you did an amazing job at making it “understandable” and I got it. Thanks a lot.

I did find a few typos however in a couple equations (at least I am pretty sure that they are typos). In equation 9, the last term (Vo(n)) should be outside of the square bracket. And for equation 10, the value of a, the last term should probably be “Delta_T^2″ and not “Delta_T2^2.”

Once again, thanks for a great article.

Cheers.

Robert Lacoste and the editorial staff thank Coulliard for pointing out the errors.

Circuit Cellar 264 (July 2012)

A reader found a mistake in George Martin’s article, “Switch Debouncing: Interfacing to a Simple Serial Device.” He  noted that Figure 2  (p. 62) includes the statement: “Is switch counter > MAX_LIMIT?” He then asked: What is supposed to happen if the answer is “No”? The answer is fairly obvious, but not shown in the Figure.  Is this a limitation of your UML charting software? Martin responded: Good catch. A missing link. You should just exit the routine.

Circuit Cellar 263 (June 2012)

A dedicated reader brought to our attention an error in a schematic (Figure 2) that appeared in Kevin Gorga’s Circuit Cellar June 2012 article. “AC Tester.” The edit shown below was contributed by Circuit Cellar reader Paul Alciatore:

The error was made by the editorial staff, not the author. Along with the edited schematic, Alciatore wrote:

While reading this interesting article I noticed an apparent error in the schematic diagram in figure 2.  The text states that the switch, SW2, allows the two transformer windings to be placed either in series for 220 V or in parallel for 110 V with higher current.  As shown, the series position does work, but the parallel selection does not.  In the parallel position only T4 is in use: T2 is disconnected.  The author’s schematic was probably correct but it looks like a line was omitted when it was copied for publication.  I have attached what I believe is a corrected schematic.