Electrical Engineering Weekly Newsletter - Monday, December 28, 2015

Top new questions this week: Does (and when how) the lifetime of a LED depend on the PWM frequency Let's assume two options for driving a standard LED at its rated current. PWM set to 50% duty cycle at 10 kHz PWM set to 50% duty cycle at 50 kHz Technically both LEDs would produce the ... led pwm lifetime   asked by Gilad 21 votes answered by Andy aka 9 votes Unusual interference I'm experiencing an effect somewhat like GSM frame-rate audio breakthrough in my auditory systems - completely different frequencies but equally wideband. I've noticed it occasionally in the past - ... interference hohoho reindeer   asked by Russell McMahon 15 votes answered by helloworld922 2 votes How to drive 1080p with only 540 pins? I was trying to hack a 3-D system starting from the monitor: VG248QE. I teared it down to LCD matrix and driver. This is a 1080p(1920 x 1080) monitor so I was expecting that at least 1080(row) + ... lcd driver monitor   asked by Alper özel 10 votes answered by JonRB 11 votes Why do DRAMs retain their state better when they are cold (when powered off)? I'm sorry if this is off-topic. It may be better suited for a computer hardware forum, but I couldn't find anything appropriate. I've been reading about the cold boot method, which can be used in ... capacitor dram   asked by Zen Hacker 8 votes answered by Respawned Fluff 11 votes Is it possible to pick up noise in an audio circuit through the ground / earth wire? In an audio circuit, such as a guitar's electronics (the only thing I ever dabble with!), I have always thought (probably simplistically) of every point along a continuous earth path being essentially ... audio noise   asked by topo morto 8 votes answered by Olin Lathrop 5 votes How plausible is the claim about a 200 kW battery solution? Following this question posted on Aviation:SE: Does the ARCA hoverboard violate known limits on small-diameter electric fans? which is related to a hovering board described on the vendor site: ... lithium-ion   asked by mins 7 votes answered by Bruce Abbott 10 votes How many ground an power pins to have in a connector? I'm designing a daughter board for a project. There are 35 I/O pins that need to goto the board. How do I determine the number of ground and power pins to include? How do I determine the placement of ... power connector ground layout pins   asked by Justin808 7 votes answered by Krunal Desai 10 votes Greatest hits from previous weeks: What is "forward" and "reverse" voltage when working with diodes? What is the difference between "forward" and "reverse" voltages when working with diodes and LEDs? I realize this question is answered elsewhere on the interwebs such as wikipedia, but I am looking ... led diodes   asked by JYelton 26 votes answered by AndreKR 22 votes Slow Blow vs Fast Acting Fuse Is there any way to tell the difference between a slow blow and a fast acting Fuse? I had one blow in my amp and I know its 125v 5a, but i'm not sure if it is a slow blow or fast acting fuse. Is ... fuses   asked by Sean 12 votes answered by Harry Weston 15 votes Can you answer these? Arduino Uno with BLE disconnected detection I am new to the development of Arduino code. I have an Arduino uno board and a BLE Bluetooth device. I was able to connect, send and receive messages my IPhone device. My arduino code open/close a ... arduino bluetooth-low-energy ble   asked by Samir Adel 1 vote May RJ45 connector with magnetics connected in series? I have a dev board with a RJ45 connector which has magnetics integrated. I need put it into a case and mount another RJ45 on the panel, sadly I have only another connector which also integrate the ... ethernet rj45   asked by diverger 2 votes How to interface with the Apple Watch for the purpose of accessing its internal memory? Unlike other apple products which can be directly connected to a PC via USB, the Apple Watch is completely wireless from the point it exits the factory, as far as I am aware. Aside from a 6-pin ... memory interface storage apple   asked by Kris 3 votes

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