Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [physical-design]

This can refer to the design of the actual transistors inside an IC. That is also called IC layout.

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How do I improve a simple home-made capacitor?

I was explaining to my son that a capacitor is simply 2 sheets of foil separated by a dielectric and rolled up and he said, "can we make one then?" I'm giving it a go. I used household aluminum foil and some parchment paper. I cut the foil into…
nuggethead
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Why would an op-amp use BJTs over MOSFETs?

I've always been told that ideally, op-amps have infinite input impedance. So when I was looking at the LM741's transistor level schematic, I was confused when they used BJTs instead of MOSFETs. Wouldn't using a BJT result in current flowing into…
Nate
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How do I design my very own ARM based processors?

I have several questions about how I would design my own ARM-based CPU? How does one start with an ARM license and end up with a package ready to be soldered on to a board? What do I get from ARM (I am sure they have multiple license options to…
Lord Loh.
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Make a custom plastic case

I have worked on many electronic DIY projects like MIDIbox (http://www.ucapps.de/), it always was fun and working but at the end, the problem was that I ended with a cool gear, but in a poor casing, for example : wood very roughly cut (by…
Basj
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What is the most amazing PCB artwork you've ever seen?

Have you ever looked at a PCB and burst out laughing? Have you ever looked at a PCB and said "Wow, that is amazing"? Have you ever seen a PCB that artistically expressed criticism of society's treatment of the poor? I'm focusing here on the PCB…
davidcary
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Why do they crimp capacitor leads?

Most manufacturers produces crimped and straight lead pairs of their capacitors which has exactly same capacitance and voltage rating. Why do they bother crimping the leads? What advantage does it make? In which cases a crimped lead capacitor should…
hkBattousai
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How do I open a rectangular hole on a metal case?

I'm working on a case design. There is rectangular switch. I am trying to open a rectangular hole on the metallic case to fix it in there. I'm not doing a good job, if it goes on like this it looks like I'm going to ruin the case at all. How do I…
hkBattousai
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SMD vs. Through-hole components in high vibration environments

This is more of a opinion question than a information question. I am designing some boards that will be working near decent sized actuators, so I ask you, what is more resistant a 0805 SMD or a 7mm thru-hole resistor?
J.P.Wack
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What makes some commercial JFETs asymmetric?

In a MOSFET, the obvious cause of asymmetry is the fact that the source is tied to the body. But in a JFET, no such obvious answer exists, as the body, gate, and drain are all the same piece of silicon with no material differences between them (as…
Hearth
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How realistic is the famous "Bill sux" picture of a chip internals artwork?

There's an urban legend that some version of Intel Pentium chip had "Bill sux" caption somewhere on the circuit. The legend is accompanied with this picture: Now let's assume for a moment that the legend is in fact true. How realistic is the…
sharptooth
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Where is the cold junction on the commercial thermocouples?

According to all textbooks and articles, a thermocouple must have a cold junction somewhere on the middle of it. But none of the commercial products have a middle point or a marked spot for indicating the position of the cold junction. They are…
hkBattousai
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What is the physical size of a logic gate?

I always hear about process size improvements in the news, but could never figure out how it translates into dimensions of a logic gate. I found a chapter from Weste's CMOS VLSI Design, that contains figures which looks like things I create when…
syockit
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What is "flush mount socket" in this 40yr old Tek scope?

EEVblog Dave shows us flush mount socketed IC's in this Tektronix 213 Portable Oscilloscope teardown, but it is hard to see and understand what exactly is a flush mount socket. Can someone explain how it is done and why? The video at 7'46" and a…
jippie
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Why is this CMOS implementation of XOR wrong?

I'm working on a problem from an ETH Zurich course. They want you to build a transistor-level CMOS implementation of a XOR gate. My attempt at this is the following: The given answer is this: Why is theirs so much more complex? I feel like I'm…
Connor
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Does PCB artwork affect operation and how is the effect validated?

Sometimes PCB designers will draw some art on unused PCB areas. Like here and here. Looks great, but does this affect schema functioning? According to answers to this question an entirely isolated stripe of aluminum foil may act as a stripe…
sharptooth
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