I started thinking about how the makers of transistors sort the different grades of transistors as they’re manufactured. I thought that a reasonable analogy would be similar to how a farmer might sort the fruit he harvests. Here’s what I came up with.
The farmer starts with the fruit his workers have gathered. The fruit is first cleaned then ‘culled’ to separate the rejects out of the good ones. These are rejected because of pest damage, non-spherical growth, too green, etc.
Then the good fruit are run through a series of different sized slots that let the fruit fall into assorted sizes. The smallest sizes are not sellable for retail price so are sent to the processing plant where they are made into canned goods. The largest fruit may be too easily damaged during shipping so they also may be shipped to the processing plant. The medium sized fruit are selected for produce for shipping to retail stores. There may be other grades selected, such as color, flavor or ripeness.
My point is that transistors are like fruit in that there are various grades that are selected from the transistors made. Some will be too high gain, some will have too low gain. The datasheet may give ranges of gain, such as 100 to 200 for gain range E, 200 to 300 for gain range F, and 300 to 400 for gain range G. The transistors may be sorted into the maximum voltage they can handle, or low noise performance. The various grades may be labeled with different type numbers according to the data sheet.
2020-01-08 Sorting Transistors Compared to Picking Fruit
