Why are there two columns for prices in the parts list?
A reader was confused by the two price columns in the parts lists. He was unsure which applied to a hobbyist wanting to do the experiments in the book.
I replied:
There are two price columns for almost every part on each Parts List. The first is the single quantity price (“Price (Qty 1) $US”) which you need to multiply by the “Qty Needed” column value to see how many you need to buy and what it will cost for a single person to do the labs. The “Qty Price $US” and “Qty” (which is the number of parts you get for the listed Qty Price) columns are for institutions equipping a lab for multiple students who plan to buy in quantity for teaching the book as a course to large number of students.
For example, the first item on the Analog Parts list is the 6.3V Transformer which cost $11.72 for a single purchase in Feb 2025. You only need one of these to do the labs that require it. However, a university lab such as the one I taught in is not going to buy just one, rather they might choose to buy 25 of them for $253.29, thus saving a bit under $40.
You can also save money by excluding some higher cost parts that are only used in one or two labs. For example, the LTC1150 op amp is $12.52 but is only used in a single lab in Chapter 7L. Another reader asked which items these are and we have now published a list to help you decide which (if any) of the more expensive parts you may not want to purchase by skipping the lab or labs that use it.