# All Questions

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### How data 0xFF is stored in Flash memory?

Hi i am using SST25VF032B flash memory. Before writing ,it has to be erased to 0xFF. But my doubt is that how it stores real 0xFF. Will is store 0xFF or some other value?
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### How to turn DC motor to specified angle

We have bought 2WD turtle bot with Arduino. http://www.dfrobot.com/index.php?route=product/product&product_id=65#.UZxObIoW3RQ Now we need to turn it to 90 angle. We need to understand how we can ...
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### NPN BJT in saturation, base voltage irrelevant?

I'm trying to build as simple a circuit as possible that will pull a logic line low every time an automotive ignition coil 'fires'. My first inclination is to simply attach the 'negative' terminal of ...
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### Substitute a MOSFET in a motor controller

I'm trying to build a CoffeeBot from MAKE magazine, and I had a question about one of the components. The circuit is pretty simple; it uses an Arduino to control a gear motor via a MOSFET transistor. ...
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### FPGA Logic Gate Count

I found an FPGA board that I liked. It uses a Xilinx Spartan 6 LX45. When I went to the datasheet for the Spartan 6 series, it only said that there were 43,661 logic cells. How many gates does that ...
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### Why are copper pours called copper pours?

I was adding a ground plane to a PCB layout today, and my curiosity peaked. Virtually every EDA package uses the term "Copper Pour." Why is it called a copper pour? It doesn't really make sense ...
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### Limits of electromagnetic computation [closed]

How do Maxwell's equations used for calculations and electromagnetic simulation push the limits of our numerical methods and computation tools? What are the modern limitations people in the field ...
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### Recommendation for ADC noise filtering?

I'm using an ADC (adc081c021) with a pretty noisy input: There is also a 5-second video here: http://tinypic.com/player.php?v=2ue47cm&s=5 The objective is to detect the two peaks. How could I ...
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### Interfacing PSD

The PDF link shown below leads to the schematic for measuring the position of a laser beam by using Quadrant PSD. Do the outputs X and Y themselves indicate the position or are they needed to be ...
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### Voltage Controlled Attenuator

I'm trying to create a DC voltage attenuator which linearly scales the loss relative to an applied control voltage "Vc". In other words, K = Vout/Vin is a linear function of Vc. Vin is guaranteed to ...
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### Double side PCB with solder via?

Normally vias are made with through hole plating. In the past they used to make vias by soldering a piece of wire to connect the top and bottom layers (like a short piece of 24 gauge copper wire). ...
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### How does this circuit multiplex an antenna between a transmitter and receiver?

I've built a Softrock RXTX kit (full schematic: pdf gif, see lower-left corner). It has one connector for one antenna used for both receive and transmit, but I don't fully understand (likely due to my ...
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### Electromagnet interference with motorcycle

I just got a sport bike which the frame is aluminum the engine is aluminum the swing arm as well. Basically this bike is made up of mainly aluminum and plastics with very little steel or any other ...
53 views

### Calling ports in C on my microcontroller

I have been developing a small OS for my lpc1313fbd48. I am sending all of the C and assembly code in a binary file. I want to be able to call the ports in C and have an LED turn on for a few seconds ...
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### Line down center of TFT display

I'm trying to connect a Sharp LQ070Y3DG3B TFT display to an Epson S1D13517 display controller. The test image and a bitmap that I've loaded are showing up fine, except there is a aqua line vertically ...
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### How does the 555 timer IC circuit work?

As a beginner to electronics I'm having a tough time understanding circuits that have a combination of different components, including the following timer circuit. Its based around a LM555 timer IC. I ...
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### How do I control a seven segment display with a shift register and an Arduino?

I recently purchased 4 seven segment displays from sure electronics. They came with their own shift register board which combines the 74HC595 IC with the ULN2003. I want to be able to tie into this ...
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### 270-360 degree servo [closed]

Does anyone know of a servo that has a range of 270-360 degrees. I cant be a winch servo and it can have less than that range. Also torque/current draw is not terribly important as long as it is not ...
41 views

### Dtmf based robot [closed]

Does any one know any thing about connecting the audio phone jack to micro-controller. I am making a DTMF based mobile controlled robot and i do not know how to connect a 3.5mm audio phone jack to ...
31 views

### Working with gEDA [closed]

I want to make a simulation of a simple Buck converter (with freewheeling diode) with gEDA & gSpiceUI. How do I do that? I'm totally new to this, it seems difficult to understand. Do you know a ...
41 views

### How do I figure out the pin usage of a power supply? [closed]

I have a broken power supply brick for an appliance. It has a 5 pin DIN connector and the label says it was OUTPUT:5VDC/1A. At least that's what I think is broken ...
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### Does skin effect distort a transmission pattern?

This question got me thinking. Homebrew ham-radio antenna is typically a monoband contraptions; perhaps SWG 16 through 21. Thinner wire is more resistive, but at HF/VHF skin effect comes into play ...
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### PCB Assembly Services [closed]

Ive been running my own PCB Assembly firm in the UK for a little while, and dealing with mainly hobbyists or inventors and so they dont tend to be to big in batch amount but also not a always a ...
34 views

### NCP59302 resistor question

What resistors do I need to get 5V on this chip? Sorry, I don't understand the reference to the Iadj in the formula. The section on the Iadj in Adjustable Voltage Design seems circular. ...
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### What are the factors that significantly affect the life span of a DC motor?

I'm currently planning to run a DC motor continuously on solar power. So I would like to know which things I should be very careful about for optimum lifespan of the motor. I found the following two, ...
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### I want to connect an HDMI mini out (on my tablet) to a VGA input in a 'smart room' that I teach in-how? [closed]

I want to connect my Asus tablet mimi HDMI to a VGA in a 'smart room' that I teach in. Can I do this so I can show art work, play you tube videos, and recorded music and PDF's on the big screen in the ...
49 views

### DC Motor Overvoltage Operation

I am new to PWM control. Is it advisable to operate a motor at higher than rated voltage with the "PWM average voltage" more than the nominal voltage specified in the datasheets? After some ...
51 views

### Same processor with different names

Following types/variants/package of P1022 freescale processors are available in market: 1)P1022NXE2LFB 2)P1022NXN2LFB 3)P1022NXE2HFB 4)P1022NXN2EFB 5)P1022NXN2HFB 6)P1022NSE2EFB 7)P1022NSN2EFB ...
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### Need help with a sub-standard RS232

I've built a UART-RS232 converter based on max232 and it works well... but not for what I need :) According to Maxim's datasheet the RS232 side signal voltage should be theoretically +/-10v (5v * 2), ...
162 views

### Why use a pull-down resistor with a LDR and microcontroller?

I am looking at this: http://learn.adafruit.com/photocells/using-a-photocell It's connecting VCC <-> LDR <-> resistor <-> GND. And the analog ...
34 views

### Mips register file implementation [closed]

I read that mips register file exploits the fact that its registers change on the opposite clock edge from the majority of the state elements. Using this fact is the basis of writing in the first half ...
16 views

### SmartCard, MagneticCard and RFIDCard Reader in a sngle module with RS232 interface

I difficult to find a SmartCard, MagneticCard and RFIDCard Reader in a single module and use RS232 interface. Most in the market is to use a USB interface, while I need RS232 interface. I want ...
118 views

### Heatsink earthing?

I'm currently working on my first circuit that dissipates enough power that I need to use a heatsink. The component in question is a TS1085CZ33 which I'm running with a maximum load of 2.8A ...
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### Building An E-Ink Wall

The Idea When I heard about Mirasol and Electrowetting the first time, I considered this techniques to be useful for building a wall-hung touch screen where you can show notes, calendarings, drawings ...
124 views

### Can we measure reflected power in a transmission line?

This is a question related to radio transmission, I hope this is the proper forum to ask it. It relates to transmission lines connecting a radio transmitter to its antenna. In his book "Reflections", ...
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### Circuits using generators and cells and capacitors [closed]

This question was in a science worksheet we had, the description read as follows: Tim has designed a generator that uses wind power and provides 9V. He decides to design a circuit using diodes ...
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### i am trying to match a power supply to a computer but cannot get the exact volts /amps/ power in a standard psu [duplicate]

As I said above, i cannot get an exact match for the computer I am trying to repair. Which is 12v @ 6.7 amps approx 80 watts. The closest I can get is a 14v -17v unit. is this higher voltage likely ...
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### Atmel Software Framework. Confusion with USART example

I'm trying to get the following basic USART example working on a SAM4S: http://asf.atmel.com/docs/3.4.1/sam4s/html/sam_usart_quickstart.html#usart_basic_use_case I am using a custom PCB board with a ...
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### Party-line / Full-duplex intercom - mixing audio signals

Party-line or full-duplex intercoms allow for the simultaneous transmission and reception of audio from all connected stations, i.e. effectively there is an audio 'bus' and each station takes a feed ...
65 views

### AC DC Analysis of diode

in the following circuit: Im looking to find what $v_D(t)$ is given $V_γ = 0.7 V$ and $r_f = 0$. Now when doing the DC analysis, find that $VDQ = 0.7 V.$ But im having trouble finding ...
53 views

### Turning OFF the grill when the espresso maker is ON

These are the variables to this problem: We have two 120 volt appliances: - an espresso machine (draws 8 amps) - and a grill (draws 12 amps). The grill is ON all the time (it actually stops heating ...
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### What is the relationship between bit error rate, frame size and normalised effective throughput?

I'm trying to write a MatLab function to calculate normalized effective throughput for a given bit error rate and frame size. A similar question was asked before here: Is there a formula describing ...
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### About Correlator and Matched Filter

When I studied Digital Communication, we were taught that, 1) matched filter is better than correlator because it does not need to be synchronized with transmitted signal. 2) correlator is preferred ...
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### Problem with the 74160 decade counter

As I am experiencing with different TTL components, I am having a ton of trouble with the 74160 decade counter. I don't know if it's my inexperience or if I'm dealing with a malfunctioning IC, but the ...
82 views

### Analysis of Shunt Circuit

I am having trouble computing the closed loop gain of the circuit below: It seems clear that this configuration is a Shunt Voltage but I just can't figure a way of computing the feedback factor and ...
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### Built-in voltage [duplicate]

Hello all I have work on the following question and just wondering if you all could check to see if i did it correctly. The built-in voltage of a GaAs pn junction diode is 1.25 V when the diode's ...
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### The value of damages caused by audio jacks and USB connections [closed]

I am looking to see what the annual value of damages caused by audio jacks. This would include repairs, units beyond economical repair which are destroyed and the lost of service.