Errata

Mouser.com catalog number 12BH410-GR is for a battery holder for a single AAA cell. The Mouser.com catalog number for a battery holder for a single AA cell (by the same manufacturer, also 6" leads-tinned 3/16") is 12BH311A-GR.

Note from the Author or Editor:
The correction is valid.

The first sentence of the paragraph reads: "We measure distance in miles or kilometers, weight in pounds or kilograms, temperature in Fahrenheit or Centigrade?and electrical resistance in ohms."

For your information, weight is a force measured in pounds-force or Newtons, not pounds-mass or kilograms.

Note from the Author or Editor:
Page 6, first para under "Fundamentals" heading, delete "weight in pounds or kilograms," and substitute "mass in pounds or kilograms,"

resistance ... is *inversely* proportional to its area of cross section

Note from the Author or Editor:
Oops! An embarrassing error. Amazing that no one saw it before.

The one-word correction suggested by the reader should be implemented.

It should state you need Alligator clips to perform the experiment.

Note from the Author or Editor:
The "You will need:" list on page 9 should be expanded to mention one alligator clip.

Is it just me or is the info about the frequency of changes from positive to negative from the 'hot' wire in a power outlet in your home mixed up?

I live in North America and I'm pretty sure ac changes from + to - 60 times a second (60hz) and in Great Britain (UK) it changes at 50Hz.

Just thought I would put it out there.

Great book!

~d

Note from the Author or Editor:
The frequency of alternating current in the United States vs. Europe was stated incorrectly on page 12. The sentence should read, "It changes from positive to negative 60 times each second (in Great Britain and some other nations, 50 times per second)."

In the printed version, the numbers 50 and 60 are reversed.

I believe the figure reference is incorrect in the sentence:

"As you turn the potentiometer up and down, you should get exactly the same results as with the configuration in Figure 1-64."

should be:

"As you turn the potentiometer up and down, you should get exactly the same results as with the configuration in Figure 1-62."

Even though the statement is true, you don't really introduce Figure 1-64 until the top of page 23.

Thanks.

PS: I'm really enjoying the book.

Note from the Author or Editor:
The reader's suggestion is correct.

In the shopping list for experiments 6 through 11 you specify on page 42 a Quantity of 4 for 2N6027 programmable unijunction transistors. The 2N6027s are used only in experiment 11 and only two are needed.

I suggest you change the "Quantity: 4" on page 42 to "Quantity: 2".

Great Book. I hope you are working on Book 2.

Note from the Author or Editor:
I was allowing for the possibility of people destroying transistors accidentally. The text should be modified:

Quantity: 4 (allowing for 2 spares in case of damage)

In the shopping list for experiments 6 - 11, you specify on page 42, first paragraph under 'Capacitors', "Electrolytic capacitors, assorted. Must be rated for a minimum of 25 volts and include at least one capacitor of 1,000 microfarands."

However, in experiment 11 (the only experiment in this series to use a capacitor other than the 1,000 microfarand capacitor) you use the 1,000 microfarand capacitor and two 2.2 microfarand capacitors.

My suggestion is change the wording to say:

"Electrolytic capacitors, assorted. Must be rated for a minimum of 25 volts and include at least one capacitor of 1,000 microfarands and two capacitors of 2.2 microfarands."

This will help reduce the number of shopping trips!

Great book BTW. My 12 year old son and I are thoroughly enjoying it.

Note from the Author or Editor:
The complaint is correct: The shopping list on page 42 should be modified as suggested.

Several other readers have pointed out this Experiment 6 LED-and-leads orientation issue already, and the author responded that it had been corrected, but I was unclear on the nature of the correction after reading the other errata. Without rehashing the problem reported by Ciochetto, Bogart and Parsons, I believe these are the specific corrections that need to be made.

(My copy of the book says 'December 2009: First Edition)

* Figure 2-17 should be revised to indicate the red lead connecting to the resistor, the blue lead connecting to the switch, and the orientation of the LED reversed (long lead connecting to the resistor, short lead to the switch).
* Photos 2-18 and 2-22 should be revised to show the red lead connecting to the resistor and the black wire connecting to the switch.
* The text on page 45 saying that the long lead on the LED should connect to the resistor and the positive side of the circuit is correct and should remain as-is.
* Schematic 2-35 on page 50, which shows the positive lead connecting to the resistor and then the LED is correct and should remain as-is.

Note from the Author or Editor:
The reader's summary is very helpful and is correct.
NOTE: Figure 2-17 has been fixed in both the printed and digital products for the 2/11 printing.
Figure 2-18 and 2-22 need to be reshot (new photographs).

In regard to the following sentence, is the conversion correct?: "Make sure you get at least one rated at 0.0047 uF (which can also be written as 47nF)."

Is 0.0047 uF equal to 4.7 nF, not 47 nF?

Note from the Author or Editor:
The correction is valid.

Both photographs of the circuit being discussed have the black and red leads from the battery swapped from the diagram in Figure 2-17. This matters because the text makes a point about which way to hook up the LED in the circuit.

Note from the Author or Editor:
This complaint is valid. The two photographs show the colored wires from the battery with polarity opposite to the diagram in Figure 2-17. The diagram should be revised to match the photographs. I apologize for this error.

If you go back to the shopping list on page 4 figure 1-10 you see a pic of 4AA battery pack(6 volt). Page 17 figure 1-44 and page 19 figure 1-51 also shows this battery pack.

When you reach pages 44 and 45 it shows what looks to be a 2AA pack. Either it is the wrong battery pack or perhaps a different style that has the other 2 on the bottom? Still it may throw a curve ball at some beginners.

good book!

Note from the Author or Editor:
This complaint is correct but the fix will entail adding one 2-battery carrier to the shopping list on page 4, and revising the list of parts needed on page 43, which should be changed to specify 2 AA batteries, and a battery carrier for 2 AA batteries, instead of 4 AA batteries and a carrier for 4 batteries.

Positive and Negative terminals are reversed from the book text. See the errata for page 44 (Figure 2-17) for more details.

Note from the Author or Editor:
As I recall, this error was previously reported and the diagram was revised for the second printing.

The text above and below Figure 2-47 state that it represents Experiment 4 show in Figure 1-50, page 19. However in figure 1-50 the LED is connected to the wiper on the potentiometer, and in Figure 2-47 (the schematic) the negative terminal is connected to the wiper. Am i seeing this correctly? If so, one is a mistake i believe.

Note from the Author or Editor:
The reader is correct, and Figure 2-47 should really be redrawn.

The Book States:
"Compare the example in Figure 2-48, showing the two DPDT switches, with the version shown back in Figure 2-35."

It should say:
"Compare the example in Figure 2-48, showing the two SPDT switches, with the version shown back in Figure 2-35."

Note from the Author or Editor:
The reader has described the error and the necessary correction correctly.

Text says that when voltage is applied to the base of the transistor it "opens" its switch and allows current to flow through the emmiter.
A switch has to CLOSE to allow current to flow through it.

Note from the Author or Editor:
Funny no one else noticed this error.

The sentence should state "The voltage at the GATE determines when the PUT allows current to flow".

Typically once the anode voltage is about 0.7V greater than the gate voltage, current will flow from anode to cathode. Thus it is the GATE voltage that "programs" a PUT.

Note from the Author or Editor:
In fact when the voltage on the anode crosses a threshold, it does force the PUT to pass current from anode to cathode. But the voltage on the gate programs where the threshold will be. This is why the component is said to be "programmable." I will add a sentence on page 83 to make this clear.

This may just be my misinterpretation.

However, the sentence "The transistor blocks it until the anode gets close to 6 volts." coupled with the discussion on page 85 about the capacitor needing 5 seconds to charge to 6 volts lead me to expect the LED to flash once every 5 seconds.Granted there was verbiage about a "threshold", but it was unspecified and I assumed that it was close to 6 volts as well.

After some poking around with data sheets and a multimeter, it looks like the gate voltage is around 3.8 V with the circuit as depicted in figure 2-103 and the offset voltage is roughly .4 V, so the 6027 triggers around 4.2 V which happens very roughly at 2 Hz (rather than the .2 Hz that I was originally expecting).

Summing up, I guess I don't consider 4.2 volts to be "close" to 6 volts.

Again, I hesitate to call this an error but I didn't see a "comment" option. Feel free to put this in a more appropriate category.

Note from the Author or Editor:
The reader is correct. On page 83 there is this sentence:

The transistor blocks it until the anode gets close to 6 volts.

Please change this sentence so that it reads:

The transistor blocks it until the anode is above 4 volts.

This was corrected from previous input is seems like but the correction doesn't seem to jive with real world experience. I don't think they way you are figuring this out is correct. Using an online calculator from http://hughestech.com/rc_calculator, I get the proper results which are about a second to charge up with the 2.2 microfarad capacitor and about 10 seconds with the 22 microfarad capacitor. Using your formula it would take almost a minute for the 22 microfarad cap to charge up. Even checking youtube videos of people showing the same circuit using the 2.2 microfarad cap, they get a flash about each second.

Note from the Author or Editor:
Page 85, printed edition, third para, delete sentence: "In this circuit, the capacitor takes about half a second to get close to 6 volts."

Page 85, printed edition, fifth para, delete sentence: "The voltage drops back down, and the PUT returns to its original state." Instead please substitute this sentence:

The voltage drops back down (although not to zero, so the ongoing cycle length cannot be predicted from the formula to establish the time constant).

On figure 2-103, 2.2uF capacitor is in series with a 470K resistor. The sentence explaining the circuit reads: "In this circuit, the capacitor takes about half a second to get close to 6 volts", which is incorrect:

t = 5RC = 5 * (4.7 * 10**5) * (2.2 * 10**-6) = 5.17 seconds

I think if the book included the computation used to get the capacitor's charging time, the error would be much easier to spot. Experimentally, the LED in the circuit indeed flashes about every 5 seconds.

Note from the Author or Editor:
I'm not sure how we made this error, but so far as I can tell, the formula supplied by the reader should be inserted, and the text should be revised to state 5 seconds instead of half a second.

Also, in the interests of not breaking pages, add a note to the right, using the THEORY style. The heading will say "Capacitor Charge Time" and the copy will say "The amount of time it takes for a capacitor to reach its threshold is calculated with 5RC, where R is the resistance (in ohms) of the resistor, and C is the capacitance (in farads) of the capacitor. So in this case, you'd multiply 5 by 470,000 by 0.0000022, which gives us 5.17 seconds." Line it up with the paragraph beginning "You may remember..."

In the circuit, L1 (Loudspeaker) needs to have its right-most wire shifted to the right and plugged into the right-most negative voltage column.

Note from the Author or Editor:
This is correct. The schematic should be modified.

In the figure, C3 (Capacitor 3) should have its right-most wire shifted to the far right negative voltage column. The same problem exists for the jumper wire at the very bottom of the circuit; it needs to be extended one column to the right. (This jumper wire error is also found in Figures 2-107 and 2-109

Note from the Author or Editor:
The complaint is correct. The schematic must be modified as stated.

I suggest replacing the word "schematic" with "circuit" or "breakboard".

Note from the Author or Editor:
I agree, the word "schematic" should be replaced with the word "circuit" in the first sentence of para 4 on page 117.

Voltage is not shown in figure 3-75

Note from the Author or Editor:
The report is valid. The voltage should be shown in exactly the same style as in Figure 3-76.

The voltage shown in figure 3-75 should
be 6VDC not 9VDC. The author has sent a new figure.

The 1K resitor R2 is not connected correctly; it goes between ground and one of the wires to the sensor switches.

Note from the Author or Editor:
The sensor switches ground the base of transistor Q1 through resistor R2. This resistor can be placed as shown in Figure 3-93 or as shown in Figure 3-95. The circuit should work either way. However, ideally the two figures should match precisely. Figure 3-95 should be redrawn for a future edition of the book.

Experiment 19 needs 1 diode 1N4148 and experiment 23 needs 4(or 8). But it's listed in the "Shopping List: Experiments 16 Through 24". Better to list "Signal diode, 1N4148 or similar. Quantity: 5 minimum." before "LED numeric displays" at page 150.

Note from the Author or Editor:
This entails only a minor revision to the text, so let's do as the report suggests.

In the first paragraph, "..the capacitor is connected from pin 7 to pin 2..." and "while removing the negative voltage from pin 7.".
I think the pin number should be 6 not 7.

Note from the Author or Editor:
Amazing that this error was not reported before now. The two references to pin 7 in the first para of page 164 (first edition) should be changed to pin 6.

Diode in schematic should read D1, not D2, to be consistent with explanation in the last paragraph on page 164

Note from the Author or Editor:
The label for the diode in Figure 4-25 should be D1, not D2. A substitute figure has been supplied.

The text states "the voltage detected by pin 5 slowly rises, so that the tone generated by IC2 gradually rises in pitch."

This appears to be backwards, as a higher voltage on pin 5 would raise the required threshold voltage to trip the comparator. As a result, the charge/discharge times would be longer, resulting in a lower frequency, and hence lower pitch.

Note from the Author or Editor:
COnfirmed.

In the 4th paragraph, reference is made to figure 4-30. Later in the paragraph it is stated that the first timer in figure 4-30 will create an oscillating on/off output 4 times per second which I assume can be restated as 4 cycles/second.. Using the stated values of R4, R5 and C4 in figure 4-30 and the equation stated on page 166 yields

1440 / (( 1 + (2x10)) x 68) = ~1.0084 cycles per second

which is the activity that I observe.

If a value of 2.2 kilohms is used for R5, a value of ~3.9 cycles/second is obtained and is also what I observe. Maybe that's what was intended?

Note from the Author or Editor:
Easiest way to fix this: Page 168, fifth line in fourth paragraph: Delete the words "four times per second" and substitute "once per second"

The resistor between the LED and ground should read R7 as R4 is already used for the resistor between pin 7 and the positive rail. This would also make the schematic agree with the bulleted note re: substitution of a 10k potentiometer.

Note from the Author or Editor:
In Figure 4-28, the resistor in series with the LED should be identified as R7. I have supplied a revised figure. No other changes are necessary.

The part list calls for a 0.047 uF polarized capacitor (C1). I assume this to mean it should have either an electrolytic or tantalum capacitor. Unfortunately, it appears electrolytics are not available in that small a valule and a tantalum capacitor at this value is priced at $18 CDN or better any place I've managed to find them listed. In reality, wouldn't any 0.047 capacitor work here, remembering to obey polarization if the particular capacitor requires it.

Note from the Author or Editor:
The schematics in Figure 4-22, Figure 4-25, Figure 4-26, and Figure 4-30 all show a polarized capacitor for C1. The reader is correct that for the value shown (0.047uF) a polarized capacitor is not available. However the parts list for Figure 4-21 does state "ceramic or electrolytic." Therefore a reader should be able to build this circuit. However, the schematics should be changed to eliminate the confusion. I have supplied new versions for the four figures.

Also on page 163 in the parts list for Figure 4-21 omit the words "or electrolytic"

The 4th paragraph discusses replacing the 68 uF capacitor C2 with a 1 uF one and the 2.2K Ohm resistor R8 with a 10K trimmer potentiometer in figure 4-41. It states that at the potentiometer's maximum resistance (10K Ohm), that this combination will generate 690 pulses/second.

Since resistor R7 is 1K Ohm in figure 4-41, I can refer to the table on page 166. The frequency listed there for a 1 uF / 10K Ohm pair is 69 pulses/second, which is the behavior that I observe.

Note from the Author or Editor:
Page 179, fourth paragraph under "Using the Reflex Tester" subhead, delete the words "...and a 1uF capacitor..." and substitute the words "...and a 0.1uF capacitor..."

As follows from correction of the error in the next to last paragraph on page 179, the values of C2 under discussion shall be ten times smaller, i.e., 0.1 uF and 1 uF instead of 1 uF and 10 uF, respectivelly.

Note from the Author or Editor:
First paragraph of p180 should be changed to:

First remove the 0.1 ?F capacitor at C2 and substitute a 1 ?F capacitor. Because you are multiplying the capacitance by 10, you will reduce the speed by 10. The leftmost digit in your display should now count in seconds, reaching 9 and rolling over to 0 every 10 seconds. You can adjust your trimmer potentiometer while timing the display with a stopwatch. When you have it right, remove the 1 ?F capacitor and replace the 0.1 ?F capacitor at C2.

The last sentence on the page reads:

"...compare the breadboard schematic in Figure 4-83 with the simplified schematic in Figure 4-84..."

The figure references should be swapped swapped: Figure 4-84 is the breadboard schematic, and Figure 4-83 is the simplified schematic.

Note from the Author or Editor:
This erratum is confirmed. The references should be swapped.

There is an unlabeled resistor that is connected to keypad number 7... it's on the far right of the circuit near the top. I think it's supposed to be a 10K but not 100% sure.

Note from the Author or Editor:
James is correct, the resistor should be 10K.

The LED arrangement in the circuit in figure 4-107 and the spots on the dice in figure 4-108 do not match. In the circuit, high signals from outputs A and B light up the bottom left, middle and top right leds. In figure 4-108, high outpus from A and B show a die with the top left, midding and bottom right spots.

While not incorrect from a technical standpoint, the dots/leds are reversed for the number 3.

Note from the Author or Editor:
The circuit does work but the depictions of dice with 2 spots and 3 spots are flipped left-to-right. A replacement for Figure 4-108 will resolve this issue. I have prepared the substitute figure.

The schematic in Figure 4-111 and the photograph in Figure 4-112 do not match. The photograph has a resistor (10K ?) running from pin 1 of the 74LS06 chip to the negative rail. The schematic does not show this connection. Conversely, the schematic shows a connection from pin 5 to pin 9 on the 74LS06 chip which does not appear in the photograph. Also, the schematic shows several connections from unused pins of the 74LS27 chip to the positive rail which do not appear in the photograph. I have been unable to get the circuit to behave correctly with either configuration, nor a combination of the two. Any advice would be appreciated and thank you for this wonderful book.

Note from the Author or Editor:
The reader is correct that there are some small variations in wiring between the schematic and the photograph. However, they should not be crucial. The additional 10K resistor shown in the photo is to prevent the input of the inverter from "floating"; it is desirable but you should get results without it. The additional connections between unused pins and positive, in the schematic, are likewise good practice, but not essential to get a result.

Without knowing more about the reader's circuit, I cannot advise him on why it isn't working.

The unused input pins of the 74LS27 and 74LS06 chips have been left floating in the photograph of the breadboarded circuit in figure 4-112.

Note from the Author or Editor:
This is correct, but there is no easy way to change the photograph at this point, and it's a minor issue.

Book says we need 2, 47 microfarad nonpolarized capacitors but not shown on schematic on page 251.

Book says we need 5 nonpolar 100 microfarad capacitors but the circuit diagram on page 251 only shows 2. It also shows a 10 microfarad nonpolar capacitor.

The book on page 249 says we need a 100kohm potentiometer with audio taper but it is also not shown on the schematic on page 251.

Note from the Author or Editor:
The circuit was modified to change some component values, but the modifications were not copied back into the shopping list. They should be. (I am surprised no one noticed this in the past 3 years.) On page 249 please revise shopping list as follows:

In paragraph specifying 47uF capacitors, omit 47uF and substitute 100uF.

In the next paragraph, omit the first two sentences, through "Quantity: 5". Attach (run on) this paragraph, commencing with parentheses, from the end of the previous paragraph.

Next paragraph, specifying potentiometer: Omit this paragraph.

Add one new bullet-point paragraph on page 249, anywhere in the shopping list, as follows:

Regular electrolytic capacitors. 100uF. Quantity: 3.

Although most problems were fixed in the PDF version, a 10 microfarad nonpolar capacitor is still missing from the shopping list and should be updated.

Note from the Author or Editor:
The reader is correct. Immediately below the photographs, the text reads:

Nonpolarized electrolytic capacitors (also known as bipolar). 100 μF. Quantity: 2.

This text should have a small insertion so that it looks like this:

Nonpolarized electrolytic capacitors (also known as bipolar). 100 μF, Quantity 2, and 10 μF, Quantity 1.

[This is a comment on the previous correction.]

In the shopping list it says 2 non-polarized 100 μF capacitors and 3 polarized 100 μF capacitors are needed. However, in figure 5-41, in addition to the 2 non-polarized and 3 polarized 100 μF capacitors there is a 100 μF capacitor with ambiguous polarity connected to the power source, which I believe should be polarized. If so, then the shopping list should be updated to indicate 4 polarized 100 μF capacitors are needed.

Note from the Author or Editor:
The errror report is correct. The shopping list should be changed to list 4 polarized 100uF capacitors instead of 3.

I believe that torque is measured in Newton*meter in Europe, not dyne. Dyne is the unit of a force in the (obsolete) cgs system.

Note from the Author or Editor:
I believe this is correct..

Please replace Figure 5-122 with this file:

(This file may not be visible until Feb 13, 2013)

http://examples.oreilly.com/9780596153755-files/new/mkel_05_122_new.png

Note from the Author or Editor:
Correct.

I have not worked with the PICAXE myself, but earlier in the book it is implied that the "pause" statement is followed by the pause-time in milliseconds. So I think that the sentence "pause for whatever number of microseconds" should be changed to "pause for whatever number of milliseconds".

Note from the Author or Editor:
Correct: It should be milliseconds. "Microseconds" was an error.

The line
let b1 = 2
should read
let b1 = 1

Note from the Author or Editor:
This complaint is valid. The error exists and should be corrected as suggested by the person who reported it.