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4
votes
2answers
194 views

High-density, light multiconductor cable: sources/suppliers/manufacturers?

I'm looking for a multiconductor cable with 30-40 conductors, optimized for flexibility and small outer diameter. Unlike say, Litz wire, most wires will carry an independent (microvolt) signal. The ...
3
votes
2answers
299 views

Connector Choice for Arduino/MIDI Bridging Interface

I'm in the early stages of planning a MIDI-mapping component that I can plug into my Alesis DM-6 drum kit so I can ultimately play it through Rock Band 3. I know there are commercial options out there,...
8
votes
1answer
894 views

Can I burn out my multimeter's µA range by using a few mA of current?

My multimeter only has one 400mA fuse protecting the µA and mA range (and a 10A fuse protecting the amp range.) Is it possible to damage the microamp range by feeding milliamps through it?
6
votes
3answers
6k views

Vias on QFN centre pad in Eagle PCB

I'm using some QFN devices in a PCB I'm designing using the Eagle PCB software. The QFN packages have a centre pad that is grounded and intended to help with thermal dissipation. When creating the ...
1
vote
1answer
226 views

Power brick with a high pitched whine

The powerbrick for my computer emits a high pitched whine. What could be causing the noise? Any way I can stop or reduce it?
0
votes
1answer
783 views

Need help initializing display on ATmega162

I have a DEM 16217 SYH-PY 2x16 character LCD and I have problems initializing it. I'm using AVR Studio 4. The 8 datalines are connected to port A of the microcontroller while the 3 control lines are ...
9
votes
6answers
2k views

Need help in choosing Flash size in a microcontroller

I need to decide upon selecting Flash size and RAM for a project. The micro controller I prefer to use is TI MSP430 series. Because of its low power consumption and value line series cost. However I'm ...
47
votes
3answers
40k views

When a battery is your power source, what is ground?

For the sake of not incorrectly connecting my power supply and damaging my board I'm going to ask a relatively dumb question. Is ground on my board the negative terminal on my battery? Explicitly ...
5
votes
1answer
8k views

SD card read/write problems in SPI mode

I am working on an NEC v850ES/JH3 controller for testing an SD card driver in SPI mode. We interfaced the SD card slot directly to the v850ES/JH3 controller without any pull-up resistors. Does it have ...
3
votes
2answers
490 views

RFID module always finds the same non-existent tag when seeking

I'm wondering whether anyone has any experience with the SM130 Mifare module. I've managed to get my hands on one, sans antenna of course, and seem to be having a few issues with it. I've got the ...
3
votes
2answers
2k views

Motor drivers and kickback diodes

I am considering buying one of the hbridge drivers referenced in the below tutorial, but when I looked at the comments underneath the second hbridges sparkfun page, kickback diodes were referenced and ...
20
votes
5answers
88k views

Powering laptop from 12V sources without inverter

This question has two parts: 1) How inefficient is it to boost 12V to 120V and then back to 12V as in using a traditional car power inverter to power a laptop (i.e. the 12V car battery power is ...
5
votes
3answers
1k views

If I'm amplifying a triangle or square wave, does the GBWP of my op-amp need to be higher?

I want to amplify a 4 MHz triangle or square wave by 2 using an op-amp. Do I need an ~8 MHz op amp, or a much higher rated (and more expensive) device to handle the harmonics?
4
votes
2answers
292 views

What's a good spectrum analyzer to learn with?

I'm trying to learn more about building RF circuits and I want to buy a spectrum analyzer. I've looked around on ebay, and a lot of them are really expensive. I'm a student, so I don't have a lot of ...
1
vote
3answers
348 views

Getting started with robotics

My brother is a senior in High School. When he visited our college. I've took him to a robotics event (inter college robotics competition). He got to see various bots designed by college students and ...
4
votes
1answer
538 views

Charlieplexing different LEDs

I have four LEDS (Red,Green,Blue,Yellow) and want to use charlieplexing to light them up. I'll use an Attiny13V which needs 1.8 to 5.5V. I think one CR2032 with 3V will be suffice for the µC. The ...
3
votes
2answers
4k views

Are MOSFETs Sensitive to heat while soldering?

I'm soldering through the hole MOSFETs in to a PCB and I don't have a temperature controlled soldering iron. So will I need to heat sink the legs as I solder them to stop internal damage. I as this as ...
78
votes
5answers
95k views

Relay vs. Transistor?

Rather basic, I'm afraid, but when would you use a relay, and when would you use a transistor? In a relay the contacts wear out, so why are relays used at all?
3
votes
2answers
344 views

I need help with this breadboard

Let me say to set the scene, that I am a complete beginner with electronics, not having done anything since my school days. I can write code, but hardware is another thing entirely. I got myself an ...
4
votes
2answers
2k views

Weird Thermal Reliefs in Eagle PCB

The thermal reliefs of my ground polygon to one of the pads of my footprint are just simply weird! I dont know what causes it? It seems to me that the lines leading up from the polygon to the pads are ...
3
votes
2answers
3k views

Why is a laser supply so tricky?

I need to build supply for ~20 laser diodes (~150 mW each), and the question is why can't we just use a constant current power source for each of them? A similar question for pulsed mode operation: ...
3
votes
3answers
2k views

Dual slope converter vs. delta-sigma converter?

I'm curious as to why dual-slope analog to digital converters are used in most digital voltmeters, like one of these when a delta-sigma converter like one of these easily exceeds the specifications of ...
1
vote
1answer
4k views

Difference between E/SP and I/SP and other variants

First post in Electronics and Robotics... I've been trying to order a DIP PIC off of Microchip (first time going directly off the website) for use with the RFM12, but I dont really know what all the ...
1
vote
2answers
4k views

Which potentiometer to chose for LCD screen contrast?

I recently obtained DEM 16217 SYH-PY 2x16 character screen. Here's the datasheet. As far as I can see, its contrast pin should be connected to voltage source over a potentiometer. How do I pick ...
8
votes
1answer
1k views

DP83848 (Ethernet PHY) 1-bit serial receive data in 10Base-T

Having trouble getting a Texas Instruments DP83848J working in 10BASE-T mode. The link partner and local status register agree that the link is in 10Mbps full-duplex mode. However, instead of ...
4
votes
4answers
471 views

Is it possible to repair a PCB which has suffered a DRC failure?

Okay, so I was a bit of an idiot while designing my PCB. The specifications of my PCB fab were 6/6 mil trace/space, and the boards did not meet this. So, below is the design for the PCB: The trace ...
1
vote
1answer
657 views

Need bin or hex file for Pic 16F648A Serial LCD

I have seen some kits and boards for a Serial LCD based on the PIC16F648A. A have a few of the chips and a few LCDs. I'm not into PIC programming, does anyone have a link to the compiled software I ...
3
votes
3answers
929 views

Darlington Array IC that can sink 1.5A

I am looking for a darlington array IC like the ULN2803a that can sink up to 1.5A. It needs to be in a DIP. Any recommendations? Its needed because i am driving a stepper motor and requires 1.2A per ...
6
votes
2answers
348 views

Power and ground configuration in a schematic

I have a schematic for a commerical circuit board, and I was curious about the following: ...
6
votes
1answer
2k views

How does an optical mouse detect movement?

Can anyone explain it ?
0
votes
2answers
2k views

Why is a capacitor placed in parallel with oscillator output?

I have a circuit board with an oscillator and I'm curious about why there is a capacitor hooked up to the output. The oscillator is a SWO series HCMOS Square Wave output crystal oscillator. The ...
1
vote
2answers
407 views

System Generator: How to make a channel selector?

I want a system with two inputs,sel and in, and at least two outputs channel A and ...
1
vote
1answer
3k views

How can I measure TVS diode for Seagate Momentus 7200.3?

I hope the TVS diode (or something like this) of my HDD's PCB is gone, so I could fix this HDD easily, but I don't know where it is. Can you tell me how to measure it? I read this but I didn't ...
2
votes
2answers
215 views

System Generator: a block similar to a three state logic

does anyone what is the xilinx block for getting a three state logic?
1
vote
3answers
5k views

How do I convert 12Vdc solar to AC?

We are using 12V DC solar power at home, and I want to use it for home appliances. Can you suggest what should I have to use for this? At present we are using 4 (12V) lights and one DC fan. Now we ...
5
votes
3answers
10k views

How to convert a floating point number to integer, using VHDL?

I want to convert a floating point number to a integer number. Basically I have a floating point number between 1 and 0, with three decimal places, and I want to pass it to a integer number as if ...
1
vote
1answer
898 views

Is it safe to keep on using AC adapter with a damaged output capacitor?

I was experimenting with my universal laptop adapter (Meind 100W) and when I switched it to 34V mode (while official max is 24V) the capacitor (25V) popped (the top opened and some white fibers spread ...
3
votes
2answers
1k views

Visual logic designer + simulation

in university we had our internal program called HLCCAD - it was very nice, and now I need to do design & debug some digital circuit and wondering what is current state of art software for that ...
1
vote
1answer
188 views

Measuring temperature of microcontroller and other large ICs

I'm going to be using a microcontroller and SDRAM IC in an enclosure that could, given some environmental variables that I have no control or knowledge of, get too hot for the devices to work properly....
3
votes
1answer
1k views

Cruise control implementation

I am doing a project that requires that I implement a cruise control system on an RC car using a GPS for feedback. I have implemented PID controllers before, but this is a little bit new to me ...
2
votes
2answers
2k views

Low voltage motor with arduino

Would it be safe to use a 1.5 volt motor with the adafruit motor shield? It is rated for 4.5 to 36 volt motors so I am unsure what will happen. Also, what would be a good way to determine the voltage ...
4
votes
5answers
2k views

USB to SPI converter

I have a chip that uses SPI for communication and would like to connect it directly to the USB port on my computer. Does anyone have experience with using a USB to SPI converter? How would I design a ...
-1
votes
1answer
10k views

How to repair a broken DVI port on my monitor? [closed]

I bought an LG452T-TF monitor about two years ago and the DVI port seems to be busted. The problems first started about a week ago. After waking my computer up from sleep the monitor only showed grey ...
4
votes
1answer
688 views

what sensors to use in touch sensitive furniture

I'm trying to make a wooden table with a touch-sensitive top, made up of a mosaic of small wooden pieces resembling scrabble playing pieces separated by thin glass separations. each wooden piece would ...
1
vote
1answer
215 views

Measuring heart rate and hacking an exercise machine to extend the grip area

Most of you are probably familiar with exercise machines that have grips for each hand so that you can take your heart rate. Imagine one for a skiing type of device...with the metal measuring grips ...
0
votes
2answers
3k views

Roland Microcube guitar amp damaged beyond repair?

My power regulated ac/dc adapter broke the other day and my friend thought it was a good idea to cut the wire from the mains adapter, trim the ends and plug this directly into the mains. he then ...
11
votes
4answers
25k views

Useful book for PCB design [closed]

Im planning on buying a useful book for PCB design. Until now, I have these two options: High Speed Digital Design Circuit Designers Companion Both books seems OK, but the first one (the older one) ...
1
vote
2answers
7k views

Short circuit protecting a class AB amplifier

I am designing a little class AB amplifier for a small circuit. This circuit is biased such that it has low crossover distortion. Below is a schematic: As you can see, I have inserted 68 ohm ...
5
votes
6answers
18k views

How to charge Laptop Li-ion Battery cells manualy?

I have received some Li-ion batteries which were originally used in Asus A2 Laptop battery original one and I would like to know if it is possible to charge each cells independently with some device ...
2
votes
4answers
7k views

Xilinx ISE - VHDL: Code template to make a ROM

I am looking for a implementation of ROM using VHDL code. I´m looking for a piece of code to make this easy example in order to make a generalization afterwards. I want to put in the ROM these values:...

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