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8
votes
4answers
15k views

How to utilize HDMI port on FPGA (basic)

Two questions. I have a Xilinx Spartan 6 FPGA which only has HDMI ins and outs. Is there some sort of guide or pre-written code that I can use to start sending images to the screen? I have no idea ...
2
votes
3answers
1k views

does a serial port have enough power to drive a comparator circuit?

I am trying to use serial port pins to power this circuit. Basically I want to send a voltage high to pin 8 when somebody "opens the box" that this circuit is in. Otherwise, it will send a voltage ...
8
votes
2answers
5k views

Ripple current in a linear power supply transformer

I'm a bit confused regarding linear supplies and their input currents (i.e. on the input side of the voltage regulator). To start with, here's a test circuit: \$R_{bogus}\$ is just to make LTspice ...
2
votes
2answers
7k views

Error caused by Scope or Function Generator?

This question may not be valid, please excuse my ignorance. I am having difficulty measuring a decent square wave at 500kHZ. The image below shows a 4 volt CMOS output with a frequency of 500kHz ...
3
votes
1answer
904 views

Terminating Transmission Lines with a Resistor

I have a large, but slow, SPI bus comprising of 8 devices. The frequency of operation is 2 MHz. As I understand, I need to ensure that the bus lines are properly terminated or reflections may cause ...
3
votes
1answer
1k views

What's the low voltage displayed by a voltmeter when only one of its probes is connected?

Recently I was toying with a digital multimeter and observed the following. The multimeter was set to measuring AC voltage with the upper limit of 750 volts. It has two probes which I will call "red" ...
3
votes
2answers
8k views

LM317 - bringing down to 0 volts (with a uC)

I am wanting to build a custom power supply for myself, and am having trouble understanding how to drive the adjust pin with a microcontroller. The datasheet for it is here: http://www.ti.com/lit/ds/...
1
vote
1answer
6k views

using avr atmega32 as web server using ENC28J60 chip

looking for help on making a website on ATMega32 using the ENC28J60 chip iam searching for more than a week .. i found many already-made projects on this, but nothing worked with me .. iam very ...
-2
votes
1answer
1k views

How do I fit a 2 bit subtractor into its expression?

Regular Full subtractor has the following: x,y as the inputs Bin - as the borrow in Bout - as the borrow out. Bout expression: x'y + x'Bin + yBin D - difference ...
14
votes
5answers
2k views

Why have electricity travel across the country at 1,150 kV?

The Powerline Ekibastuz–Kokshetau in Kazakhstan holds the record for having the highest operating transmission voltage in the world, running at over 1 megavolt. Why did they choose to deliver energy ...
0
votes
1answer
495 views

dust sealed connectors for PCB to wire, and wire to wire

I am working on a solar car, and I have been going back and forth on what connectors to use to seal out the dust, and keep the wires together during extreme vibrations. I am looking for wire to board, ...
8
votes
1answer
897 views

Confused by transistor behaviour

Noob question coming up... I have connected a digital output pin on my Arduino board to the base of an NPN transistor (BD135). There is a 9v battery connected between the collector and emitter, along ...
3
votes
1answer
5k views

Information (datasheet) about stepper motor?

I've got stepper motor from a friend. But unfortunately, neither my friend or I know what kind of stepper motor it is, how much current it needs and on what voltage it operates. Do you have any idea ...
0
votes
1answer
328 views

ModelSim for XILINX 12.1 design suite

I've downloaded XILINX ISE 12.1 but I am facing problems with Modelsim. I've download it as well but there's no set up file in the Modelsim folder. How I get this installed? Do I have to install ...
1
vote
3answers
864 views

Transistor level convertor

I need to build fast level converter, 5V in -> 12V out using transistors. I've seen Voltage level shifter , but it drives output high using resistor pull-up, and it's slooooow.... I have 100-1000pf ...
2
votes
1answer
4k views

Putting two wall-warts in series?

I'm helping a friend make a 48 inch hot-wire foam cutter. He would like it to be as economical as possible, so I'm giving him two 15V 1.1A wall wart power supplies that I have sitting around. I don't ...
3
votes
2answers
352 views

Is it normal for a micro SD card to have higher write speed for the first blocks?

I'm using a micro SD card of 4Gb from Kingston in an embedded project and I'm accessing it with a low level SPI driver. Everything is running just fine, except for a weird behavior: after a given ...
4
votes
1answer
5k views

What is Normalized DC Current Gain (as oppossed to DC Current gain)?

I have a table that presents DC Current Gain for BC548B transistor: and a graph that presents Normalized DC Current Gain: Are those two things related? What does "normalized" mean? Why is the Y-axis ...
3
votes
3answers
2k views

9V AC stabilizer

I've got a power supply: IN: 220V AC OUT: 9V AC 1A Note that the output is AC, not the conventional DC output. It has no regulation systems built in (simple transformer). I'm looking for a circuit ...
5
votes
1answer
4k views

PORTB Interrupt On Change changes state unintentionally

I am running below code in a PIC16F887 that runs at 20 MHz. I feed PORTB.0 a signal of 1 KHz from my signal generator. However, whenever the signal is low, ...
5
votes
2answers
2k views

Transmission line for UHF TV antenna

I have a UHF TV antenna for ISDB-T Digital TV reception. The transmitter just one only antenna is 70km away and some channels suffer from some "digital noise". That's it, the image is not perfect and ...
2
votes
2answers
335 views

Weird overflow behavior of character type variable

I am trying to design an ON-OFF Keying decoder for an RFID reader project I've been working on. Below is the code that runs on a PIC16F887 @20MHZ. The compiler is Mikroelektronika mikroC PRO for PIC. ...
1
vote
1answer
2k views

Building multiprocessor motherboard

I would like to build a multi processor motherboard using ARM processors (e.g. the ARM Cortex A8 or A9 or others as well), for low-power computing. Is this possible ? I mean interconnecting the ...
0
votes
0answers
46 views

Digitally programmable switch using minimum space (without relays) [duplicate]

Possible Duplicate: How to short two nodes electronically I want to make a pcb containing about 32 switches (that do a physical connection between wires) each can be programmed digitally from an ...
3
votes
3answers
580 views

How to short two nodes electronically

I am using a Phillips SAA3010 IR transmitter IC to send a modulated IR signal. The IC has two types of inputs: Z0---Z3 X0---X7 And one type of output: DR0---DR7 Each legal operation corresponds to ...
3
votes
1answer
269 views

API portability for ARM Cortex (Xilinx Zynq 7000) with PowerPC (Xilinx Virtex 4)

Are the APIs(or tools) used by "PowerPC Hard Macro" to integrate with Virtex 4 similar in the case of ARM Cortex with Artix 7(in Zynq)? Ideally it would seem so since Xilinx would keep it that way ...
3
votes
1answer
742 views

An IC that would combine a counter and a decoder

I have a circuit that makes uses of a decoder to command the latch line of 8 latches. To avoid spurious latching that could occur in transitions, I disable the decoder output while I change the input ...
4
votes
2answers
277 views

Can solar panels be wired serially?

I have several small solar panels. I would like to configure them in series to build up enough voltage for a project. But some panels are much smaller than others. Is there a problem of connecting ...
3
votes
1answer
4k views

Is possible to use Ipad touch screen with PIC16F707 MCU for DIY ?

I'm developing a project that I would like to use the Ipad capacitive touchscreen(digitizer) with mTouch controller PIC16F707 but by now I have no clue about the specifications of Ipad touch screen. I ...
4
votes
4answers
4k views

Wrong outputs in VHDL entity

I have lessons about VHDL in one of my university class and I have to write simple entity which will generate clock from 1MHz source. I'm using CoolRunner-II CPLD ...
2
votes
6answers
11k views

How do I get a constant current of 2mA; output voltage of 9V dc?

I need a device that can run on batteries (probably one or two 9V batteries) that will provide an output voltage of about 9V but, more importantly, is constant current of 2mA. This will be dc output. ...
3
votes
2answers
1k views

PIC assembly code simplify

I need to convert the following PIC assembly code (below) to an 8051 assembly. It is an inline assembly code. Actually, I intend to convert it to C. I am not familiar with the PIC MCU so I do not ...
1
vote
1answer
3k views

Parallel Operation Problems

How do I set up a Woodward 2301A load sharing device when operating generators in parallel? Currently, when running two generators in parallel, the first generator takes too much load, and the second ...
8
votes
1answer
3k views

Circuit Analysis Shortcuts

I am slowly learning how to analyze circuits but I am wondering if my goals are unrealistic. My main reason is to help me repair circuits boards that I come across in my line of work. (I repair coin-...
17
votes
6answers
28k views

Using the ATMega328 with the internal oscillator?

I have a project that I think would be best suited for an ATMega328P. However, in every simple project I've seen, people always hook up a 16MHz external oscillator. From what I can see, it should have ...
2
votes
2answers
16k views

Using Arduino UNO as a USB to TTL converter for unbricking a Seagate Barracuda 7200.11 Hard Drive

Is it possible to use an Arduino UNO as a USB to TTL converter for unbricking a Seagate Barracuda 7200.11 Hard Drive And if it is possible : how to program it? The Arduino UNO has no FTDI chip. In ...
99
votes
4answers
53k views

Why Are Ethernet/RJ45 Sockets Magnetically Coupled?

As the title says really, why do ethernet sockets need to be mag-coupled? I have a basic understanding of electronics, but mostly, I can't figure out the right search terms to google this properly.
3
votes
4answers
514 views

Low-cost, low-current solution for dropping 1V from a battery

I have a 3 x 1.5V NiMH battery pack giving a supply voltage in the range [3.0V ... 4.5V] depending on the remaining capacity. In order to prolong battery life I need to cut power from the entire PCB ...
4
votes
2answers
6k views

Is it possible to have 16 simultaneous PWM outputs on a 64-pin STM32F4 device?

From the STM32F405xx/STM32F407xx datasheet, I read that (at least) TIM2, TIM3, TIM4, and TIM5 have output compare units that can be configured to produce PWM signals on 4 channels each. If one ...
13
votes
13answers
11k views

What can I use to detect pinpoint location (inches) outdoors?

I am getting back in to EE after some time so please excuse my ignorance. I am looking for a way to detect pinpoint location outdoors to navigate a robot for a project with my sons. Is there a low ...
1
vote
2answers
14k views

Replacing atmega8 with atmega328(arduino)

I was supplied with an arduino board in a workshop(which is a very old version board) similar to : the board comes with atmega8 as a micro controller .. I wanted to increase the performance and ...
7
votes
4answers
13k views

Should NC-Pins of IC connected to ground through a resistor to prevent noise?

I wonder if unused pins of an IC, lets say an NE555 f.e., should be connected to ground via a resistor to prevent noise or not. I have an AVR with analog inputs and just realized there's huge noise, ...
3
votes
1answer
678 views

How does CAT6 cable extend the range of an HDMI cable

Why is an un-powered CAT6 cable able to extend the length a video signal can be transmitted compared to a HDMI cable? Is the limitation on high speed data transmission cables such as HDMI mainly due ...
2
votes
3answers
5k views

Diagnosing cause of electrolytic capacitor failing

I am hoping somebody could help me diagnose the cause of failing electrolytic capacitors in a circuit. The context is a charger circuit, more specifically its power supply unit: Given a diode bridge ...
2
votes
2answers
938 views

Trrs spec - audio jack

It is possible to use audio jack output to give power to a microcontroller? How many milliAmperes it feeds?
7
votes
6answers
38k views

How electrons inside copper wire behave when source is ac or dc?

When a simple copper wire is connected to AC or DC, what actually happens to the electrons inside the wire? I.e. What kind of path do they follow when they reach the end of the wire? If anyone can ...
1
vote
1answer
4k views

Configuration Settings of 18F4550

I have the following config values for 18F452 on my code; ...
2
votes
1answer
2k views

How can i measure voltages on each phases of a 3 phase system, Using a microcontoller?

How can i measure voltages on each phases of a 3 phase system. The measurement is to be processed by a microcontroller. Is there any special chips available, or do i need to use the ordinary ...
2
votes
1answer
864 views

How to write a simple feedback loop in difference equation?

I know how to write a simple close loop transfer function which is http://en.wikipedia.org/wiki/Control_theory Now I need to do it in difference equation form, like the equation in http://en....
1
vote
1answer
1k views

how to resolve 64 bit address of remote xbee using Arduino xbee library

Does anyone know how to resolve the 64 bit address of a remote xbee (series 2) using the Xbee Arduino library (http://code.google.com/p/xbee-arduino) ? The getRemoteAddress() public function of class ...

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