Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

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1500 questions
22
votes
5 answers

How can we test the lifespan of electrical components?

We work with some electronic devices in our projects. We are at the stage where we need to create some test strategy to validate the lifespan (e.g. 1 to 5 years) of our devices for which we provide warranty. We need to standardize this test strategy…
MKSJ
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22
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2 answers

ADC is detecting a sine wave as several clusters of points

I'm using an ADC (ADS4129) running at 125MSPS. I'm applying a 100kHz sine wave to a low pass filter (fc=15MHz). The ADC is being driven differentially, as intended. When probing the input signal with a scope I see a decent sinusoid. My problem is…
user264107
22
votes
4 answers

Difference between negative terminal and copper ground?

What's the difference between Negative and Ground? Like a negative terminal and a copper ground? I was reading that they are both the same; one person stated that negative is just more negative than ground. What's the difference? Do I even need…
John
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22
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8 answers

Why did they design new connectors for USB?

At the time when the USB standard was being developed, there were a number of widely-available connectors that they could have used instead of making a new custom connector. Why did they not use mini-DIN or DE-9 or some other common connector of the…
Hearth
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22
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7 answers

C - wrapping globals in a struct?

A firmware style question concerning C. I have some legacy code I am tidying up. One of the nasty features is global variables being scattered through the source files. I can make a few of them locals, which is fine. However, how to deal with the…
Dirk Bruere
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22
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5 answers

How to communicate faster than the system clock

I was reading about the new (ish) Thunderbolt 3 today, and was very impressed by the specced speed of 40Gbps. Then I looked at Intel's latest i9 processor speed... about 4.2GHz max. How can a system communicate almost 10 times faster than the clock…
Isaac Middlemiss
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22
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6 answers

Where do overtones in a 555 generated square wave come from?

I have built a 555 oscillator and connected it to a speaker. Using an oscilloscope I adjusted the 555 to generate a 2.5kHz square wave. I then held a microphone up to the speaker and fed the input into a spectrum analyser. What I expected to see was…
JShorthouse
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22
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4 answers

Why do we need hardware programmers?

I use a Boarduino and a 30-row bread board to program my ATtiny. I load a not too complicated sketch called ArduinoISP (included by default now in the Arduino IDE), and suddenly I have a working programmer. Atmel sells a nice programmer for…
Jack Schmidt
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22
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5 answers

Cortex-m3 toolchain

I am looking for a free (as in freedom) tool chain for Linux (Ubuntu) that allows me to develop for an ARM cortex-m3 (lpc1343) microcontroller. Where do I find such a toolchain? Are there any tutorials?
txwikinger
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22
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6 answers

Can I disable a battery powered device by reversing half of its batteries?

When I have a device that is powered by two batteries, can I disable it by turning one battery around? For illustration, the purpose is to leave batteries in the device for storage, but it does not have an off switch. There are multiple solutions…
Volker Siegel
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22
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5 answers

Astable 555 circuit not oscillating

I'm a complete beginner to electronics, but I'm trying to follow Ben Eaters video series "Building an 8-bit computer". I tried to do the first part of an astable 555 timer, but the LED does not oscillate and on top of that the timer draws A LOT of…
Mr Filp
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22
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2 answers

Why do we need a voltage divider when we get the same voltage at the output as the input?

I am using a voltage divider circuit of 100 Ω and 10 kΩ resistors, and using their output for the (IRF740) transistor's input. I'm trying to figure out why do the resistors have those specific values. It makes sense that if I use voltage divider, I…
Edi
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22
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6 answers

Does Impedance Matching Imply any Practical RF Transmitter Must Waste >=50% of Energy?

According to the maximum power transfer theorem, when a fixed source impedance is given, the load impedance must be chosen to match to the source impedance to achieve maximum power transfer. On the other hand, if the source impedance is not out of…
比尔盖子
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22
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10 answers

STM Microcontroller burns every time

I have some experience working with stm32 but I only ever used them on dev boards. I recently tried to solder stm32 and stm8 on a simple break-out board and program them with my st-linkv2 clone. On first power up, the mcu makes some little noises…
NXP
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22
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7 answers

Why is USB Type-A to USB Type-A never used?

I was wondering why almost all USB cables that exist are USB-A to (Micro-USB | USB-C | USB-B | etc.) Why was USB-A to USB-A not a popular thing? Is there a technical reason this cannot work?
NessDan
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