Electrical Engineering Stack Exchange
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1500 questions
23
votes
4 answers

Whats the standard for denoting the orientation of an LED on a PCB?

Whats the standard for denoting the orientation of an LED (or diode in general) when printing a PCB? I'm drawing up a design for students to use in a course and want to make sure I'm not misleading them.
kaytea
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10 answers

How to make a dummy load of 1000W - 2000W?

I need to check a 48V battery with dummy loads of 1000-2000 watts for 5-10 minutes. Perhaps using Nichrome wire, i can wrap some around a fire brick submerged in plenty of water and adjust the load by changing the length used?
bandybabboon
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4 answers

What is the best USB transfer type (bulk, interrupt, Isochronous Transfers) to be used for implementing a USB oscilloscope?

I want to build a USB oscilloscope. I was reading about different USB transfer types. Which transfer type is best to transfer the collected ADC samples from a USB oscilloscope to a PC? Below are a few of my findings. Please correct me and also it…
robomon
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4 answers

What and Why's of termination?

I am new to electronics, and don't understand what is termination and why it is needed, especially in digital communications. Thanks
sumeet
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23
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10 answers

Cheap 1MHz oscilloscope

I'm learning electronics (and basic electricity) and I wondered if a 1MHz oscilloscope like the DSO Nano is enough for (very) basic electrical and/or electronic circuits. I'm almost broke and I need a cheap portable oscilloscope to try various…
interlol
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23
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7 answers

Do digital multimeters require calibration?

This article Understanding Digital Multimeter DMM Specifications / Specs mention A digital multimeter will only be able to meet its specifications when it is within a certain environment. Conditions such as temperature, humidity and the like will…
user275517
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14 answers

Do we know what a radio wave looks like?

In precalculus class, we are learning about sin/cos/tan/cot/sec/csc and their amplitude, periods and phases shifts. I've studied electronics on and off for about a year. I would like to know if we actually know what waves look like. Do they actually…
Foo Fighter
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23
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2 answers

How does an FTDI chip work?

Someone asked me the other day how an FTDI USB to serial UART works, and I realized I didn't know. I looked at the datasheet for the FT232R and the block diagram didn't really help me. Can anyone explain or link me to a good explanation?
aloishis89
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23
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6 answers

What are some common/popular/go-to switching voltage regulators?

So I've used the popular linear regulators (7805, LM317, LD1117, etc), but I'd like to learn more about switching regulators. Are there any "must have" switching regulators out there that are as popular, as ubiquitous as those common linear ones?
Craig
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Why does ST recommend 100 nF decoupling capacitors for a 72 MHz MCU? (And not 10 nF.)

I've been reading about decoupling capacitors, and I can't seem to understand why ST recommends 100 nF decoupling capacitors on a 72 MHz ARM microcontroller. Usually 100 nF decoupling capacitors are only effective up to about 20-40 MHz due to…
Mike
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4 answers

Is it possible to reverse engineer a chip design?

Can we make something like chip reader, which can understand chip design and generate blueprint of it?
Kulin Choksi
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23
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4 answers

Why is the + sign commonly used as logic OR operator?

A few days ago I was asked, why it is pretty common to use the + instead of the v symbol as the boolean OR operator in digital logic. His argument was, that it is totally counter intuitive to use + for OR, because it is more likely to be interpreted…
Rev
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2 answers

How do I make the Fairchild FSA9280/FSA9480/FSA880 BOOT pin trigger? (Samsung Galaxy S)

this is a bit of a long shot but I'm hoping someone has access to the full data sheet for one of the chips listed in the title, and can tell me what combination of VBUS_IN and resistors on ID_CON will make it trigger the BOOT pin on the chip.…
TheBeano
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3 answers

Do all microSD cards support SPI mode?

Have you ever encountered an SD card which does not support the SPI mode? I read microSD are not required to but I believe all do support SPI. EDIT: The information about optionality of SPI seems to come from Wikipedia and was recently removed (here…
jpc
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Capacitance between Earth and Moon

Is there a capacitance between the Earth and the Moon, and if there was enough potential difference, could a discharge strike occur?
skyler
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