How do I know if I need one, and if so, what size and where should I go?
This question mentions several chips that need one between VCC and GND; How do I know that a particular chip is one?
Will the SN74195N 4-bit parallel access switch register used with the Arduino need one? (to use my current project as an example) Why or why not?
I feel like I’m starting to understand the basics of resistors and some of the places they’re used, what values to use in the places mentioned, etc, and I’d like to understand capacitors at the basic level as well.
I was the one who asked this question. This is my initial understanding:
You can connect capacitors via VCCVCC/GND to try to keep the voltage constant. Under the DC circuit, the capacitor acts as an open circuit so there is no problem with shorting there. While your device is running (VCCVCC = 5V), the capacitor is charged to capacitance and waits for a change in voltage between VCCVCC and GND (VCCVCC = 4.5V). At this point, the capacitor will be discharged to attempt to return the voltage to the charge level inside the capacitor (5 volts). This is called “smoothing” (or at least that’s what I call it) because the change in voltage will be less noticeable.
In the end, the voltage will never return to 5V through a capacitor, rather the capacitor will discharge until the charge inside it becomes equal to the supply voltage (for equilibrium). A similar mechanism is responsible for smoothing if VCCVCC increases more than average (possibly VCCVCC = 5.5V perhaps).
As for why you need them, they are very important in high speed digital and analog circuits. I can’t imagine you’ll need one for the SN74195, but it can’t hurt!
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