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1500 questions
31
votes
9 answers
Does wire color matter in electronics?
I'm fairly new to electronics here. But I can't seem to find any clear answer anywhere on the internet.
Are wires special depending on their color? Or they have all the same purpose with just colors to define them so people won't get confused? Say I…
William Gregorio
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31
votes
7 answers
Why are FPGAs so expensive?
I mean compared to ICs (ASICs) with similar complexity, speed etc. Let's compare Ethernet switches to Kintex FPGAs (note that the most expensive switch from the list is circa as expensive as the cheapest Kintex):
FPGAs are well structured ICs (like…
betontalpfa
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31
votes
8 answers
Can I reduce voltage from 3.3V to 1.8V using a 1.5V battery?
I am interfacing to an EEPROM that works via SPI at 1.8V; unfortunately I do not have a 1.8V power source around and being this a weekend project, I wanted to complete it without going to the shop.
I asked a skilled friend an advice and he suggested…
gdm85
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31
votes
7 answers
Finding air wires in Eagle
I am almost done routing a board. However, Eagle is telling me that there is still one more wire. I have looked but I just can't seem to find it. Is there a way to make Eagle tell me where it is?
Alexis K
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31
votes
7 answers
Smart ways to detect a button (less power consuming)
During a meeting for a particular project I was asked to think about the way to detect a push on a button with a MCU. The detection should consume as little power as possible. At the first glance, I thought the typical circuit with a pull-up or a…
vionyst
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31
votes
4 answers
Why are the high voltage overhead power lines with the same potential being isolated?
Photo #1
Photo #2
Photo #3 - A zoom of Photo #1
Photo #4 - A zoom of Photo #2
I shot these photos while travelling in a highway. In each line-group has three separate lines. I think that the three lines in each group carry the same electrical…
hkBattousai
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31
votes
5 answers
SPI bus termination considerations
So, in my previous question I asked about using the SPI bus over a short distance for board to board communication. I was recommended to try termination resistors. I placed a resistor close to the destination (but not exactly there, there was a…
Saad
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31
votes
6 answers
Why do some EMI/RF shields have holes on the top and some don't?
I am not talking about cutouts for tall components. I don't think they are for ventilation as they are often covered with manufacturer labels.
Dojo
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31
votes
5 answers
How do I fix an Omron d2fc-f-7n microswitch from unwanted clicks?
Omron d2fc-f-7n microswitches are used in computer mice all around, and they eventually start clicking several times per hit. AFAIK there is a flexible metal plate that wears out due to metal fatigue, so there must be a way to prolong its life.
The…
user1306322
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31
votes
13 answers
Taking apart old electronics
I sometimes end up having someone's unwanted old electronics, usually faulty ones. Does it make sense to harvest components from such. Anything valuable I should be looking for?
Petteri H
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31
votes
4 answers
How do I determine the area of copper needed on a PCB to provide adequate heatsinking for a power SMD MOSFET?
I am planning to use the IRFR5305PBF Power MOSFET (http://www.irf.com/product-info/datasheets/data/irfr5305pbf.pdf) to switch on a load. I have determined that I need an external heatsink with Rthsa < 29 C/W.
How would I go about determining the…
dla59
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31
votes
5 answers
Why don't we see faster 7400 series chips?
The 74HC series can do something like 20MHz while 74AUC can do something like maybe 600MHz. What I'm wondering is what sets these limitations. Why can't 74HC do more than 16-20MHz while 74AUC can and why can't the latter do even more? In the latter…
Anthony
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31
votes
6 answers
Noise reduction strategies in electrophysiology
When recording electrical signals from cells (in a dish or inside a living human or animal body), one major problem is to increase the signal to noise ratio.
These signals are usually in the 10uV to 100mV range and are generated by very low power…
Ali
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31
votes
5 answers
What is a "100R" resistor?
Sometimes I see references to "R" resistors. For example:
Obviously the 100 refers to 100 Ohms. What does 100R mean?
Tyler Durden
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31
votes
10 answers
Free IDE for VHDL and Verilog
I am interested in learning VHDL and Verilog. I was wondering if there is any free IDE for those?
itsaboutcode
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