Integrated Circuits are usually called ICs or chips. They are complex circuits which have been etched onto tiny chips of semiconductor (silicon). IC (Integrated Circuit) is Component active electronics consisting of composite hundreds or even millions of transistors, resistors and other components being integrated into an Electronics Circuit in a small packaging. Forms of IC also vary, ranging from 3 Legged to hundreds of legs (terminal).

IC functions are also diverse, ranging from amplifier, switching, and controller to media storage. Generally, IC is electronic components are used as brain in an electronics equipment. For example, IC that function as brain on a computer called as Microprocessor, consists of 16 million transistors and that number has not yet been included other electronic components.
All components with PU code are IC, but the code function is different, a lot of PU on the motherboard. So, for beginners, you should creative to take one sample motherboard and see how much PU in the motherboard, then take a look datasheet to know the function and how it works. As time passes you will know the function of each PU with its code, because it is only a few IC manufacturers use in laptop motherboards like Realtek, Broadcom, Atheros, TPS, Maxim etc.
Where is pin number 1 on an IC ?
Here is a basic rule that applies for most integrated circuits. There’s a polarity mark somewhere, from that polarity mark, move counter clockwise around the chip and number the pins starting at one.
A common polarity marker is a half-moon shape at one end of the chip. Another is a small dot by pin 1, or sometimes a small triangle or tab instead. Sometimes several of these marks can appear.

The pins are numbered anti-clockwise around the IC (chip) starting near the notch or dot.
For all IC packages, pin numbers increase sequentially as you move counter-clockwise away from pin 1.



Surface-mount ICs might come in QFN, SOIC, SSOP, or a number of other formfactors. These ICs will usually have a dot near pin 1.



IC functions are also diverse, ranging from amplifier, switching, and controller to media storage. Generally, IC is electronic components are used as brain in an electronics equipment. For example, IC that function as brain on a computer called as Microprocessor, consists of 16 million transistors and that number has not yet been included other electronic components.
All components with PU code are IC, but the code function is different, a lot of PU on the motherboard. So, for beginners, you should creative to take one sample motherboard and see how much PU in the motherboard, then take a look datasheet to know the function and how it works. As time passes you will know the function of each PU with its code, because it is only a few IC manufacturers use in laptop motherboards like Realtek, Broadcom, Atheros, TPS, Maxim etc.
Identification of a good or bad IC should be with schematic to know the input pin and outputs
Where is pin number 1 on an IC ?
Here is a basic rule that applies for most integrated circuits. There’s a polarity mark somewhere, from that polarity mark, move counter clockwise around the chip and number the pins starting at one.
A common polarity marker is a half-moon shape at one end of the chip. Another is a small dot by pin 1, or sometimes a small triangle or tab instead. Sometimes several of these marks can appear.

The pins are numbered anti-clockwise around the IC (chip) starting near the notch or dot.
For all IC packages, pin numbers increase sequentially as you move counter-clockwise away from pin 1.



Surface-mount ICs might come in QFN, SOIC, SSOP, or a number of other formfactors. These ICs will usually have a dot near pin 1.

