Step 10: Integrated Circuits

Picture of Integrated Circuits
An integrated circuit is an entire specialized circuit that has been miniaturized and fit onto one small chip with each leg of the chip connecting to a point within the circuit. These miniaturized circuits typically consist of components such as transistors, resistors, and diodes.

For instance, the internal schematic for a 555 timer chip has over 40 components in it.

Like transistors, you can learn all about integrated circuits by looking up their datasheets. On the datasheet you will learn the functionality of each pin. It should also state the voltage and current ratings of both the chip itself and each individual pin.

Integrated circuits come in a variety of different shapes and sizes. As a beginner, you will be mainly working with DIP chips. These have pins for through-hole mounting. As you get more advanced, you may consider SMT chips which are surface mount soldered to one side of a circuit board.

The round notch on one edge of the IC chip indicates the top of the chip. The pin to the top left of the chip is considered pin 1. From pin 1, you read sequentially down the side until you reach the bottom (i.e. pin 1, pin 2, pin 3..). Once at the bottom, you move across to the opposite side of the chip and then start reading the numbers up until you reach the top again.

Keep in mind that some smaller chips have a small dot next to pin 1 instead of a notch at the top of the chip.

There is no standard way that all ICs are incorporated into circuit diagrams, but they are often represented as boxes with numbers in them (the numbers representing the pin number).

hottroc3 years ago
"by looking up their datasheets"... you make it sound so simple. Lots of times I have tried to find datasheets on various components with no success. Either I can't find them at all or someone wants to charge me a fee (subscription/membership or one off extortionate charge or something) to download it. OR else there is no marking on the component to identify it, or lots of markings that can't be traced or whatever.

To be constructive....maybe you could add some links to some suitable places to lookup datasheets if the manufacturer is no help or not available? Thanks.
randofo (author)  hottroc3 years ago
I do link to octopart.com. I suppose I can link there more.

I can't help that some components don't have easily attainable datasheets. Resolving that issue goes far beyond the scope of this Instructable.

For most common components, you can find datasheets freely available in numerous locations.
AaronB8 randofo8 months ago

You can also find a number of datasheets at componentsearch.com if they can't be found on octopart.

hottroc randofo3 years ago
Hi, yes I hadn't read the whole instructable when I posted the comment and saw your link in a later step, many thanks.
FrankenPaper10 months ago

In Step 10 the link to the Schematic of the 555 timer IC chip is terrific! I am making it my screen saver!