2
votes
3answers
116 views
Do I need to use thermals on vias for reliability?
This question is further to Why thermal reliefs on vias?
I have recently been advised (by someone I consider an expert) that I should add thermal reliefs to vias which are connected to planes, even ...
-2
votes
0answers
35 views
How to design a filtered power supply? [closed]
The filtered power supply that must be design can produce dc output voltages of +10V (+-) 10% and -10V (+-) 10% with a maximum load current of 50mA. The voltages are to be switch selectable across one ...
0
votes
3answers
67 views
Synchronizing SPI ports for higher data rate
I am designing a new board which uses the NXP LPC4330 (Cortex M4 microcontroller) with a XESS Xula2 FPGA development board. In this design, the Xula 2 has limited I/O pins since it is designed to fit ...
6
votes
4answers
103 views
Can I achieve a one shot button without a 555?
I have a complex circuit, but my problem only relates to one small part.
I have a relay, which is energised by pulling the low side low using an NPN. I would like a pushbutton to operate the ...
-2
votes
1answer
80 views
what is the gain of this amplifier at resonance frequency?
I want to analyze this circuit but I do not know how to compute its gain at the resonance frequency.
In lab its gain at resonance frequency (910kHz) was 54.
5
votes
4answers
194 views
What's an easy way to supply power to a breadboard without using batteries?
There are a number of kits available (for example sparkfun's Breadboard Power Supply USB - 5V/3.3V and Breadboard Power Supply 5V/3.3V or Adafruit's Adjustable breadboard power supply kit - v1.0) but ...
0
votes
1answer
76 views
What kind of oscilloscope is good? [closed]
I want to buy an oscilloscope as a gift of Father's Day to my Dad. I have no idea what kind of oscilloscope is good? Is there any kind-hearted friend can help me? Thank you in advance!!! :-)
-1
votes
0answers
44 views
Temperature sensor issue [closed]
I am implementing home automation using an MSP430F2274. For that I need to read a temperature sensor and send the values to the receiver side. Please suggest any manuals to write code?
-3
votes
0answers
37 views
How to Start with Pic18f controller and ENC28J60 configuration [closed]
I am a newbie to ethernet control operation using pic18f controller and dont know how to configure my Olimex ENC28J60-H Board with PIC18F controller using SPI communication. However i have written ...
0
votes
1answer
34 views
Kicad: How to add a Filled Zone around a Net with a single pin?
I am designing a PCB in Kicad and I need to add a filled zone around a single pin (pin needs to become part of the zone, not an island).
For some reason, when the "Copper Zone" tool provides me with ...
0
votes
1answer
66 views
Is it possible to build a CPU from content-addressable memory?
Every modern programming language use objects and not C/C++ style struct/class.
In C/C++ every data member has a size, so addressing a struct member is basically a memory address + offset. But script ...
1
vote
1answer
71 views
Speed control for high power DC brushed motor
I am going to drive and bi-directionally control the speed of some 12V/24V, 100W to 300W DC brushed motors.
I have some experience in controlling small DC motors (6V/9V/12V, 0.5A to 2A) with PWM ...
4
votes
1answer
52 views
How to calibrate an optical particle sensor (Mie scattering)
I have a very simple sensor that basically emits infrared light (1 micron wavelength in the infrared range). The light scatters off particles whose diameter is of the same order of magnitude as the ...
6
votes
3answers
206 views
How does this circuit diagram work?
I don't understand this circuit diagram here, but I'm sure that you can help me out.
I'll explain what I have figured out so far.
EDIT: It's a metronome circuit. Sorry for being unclear about that.
...
0
votes
2answers
177 views
basic math question about voltage, ohms, resistance
total n00b here. After working on several projects by copy & paste from other people's schematics and code, I'm finally digging in and learning some of the math to know what I'm doing.
If I have ...
0
votes
2answers
47 views
Non-clock signals routed into the clock tree
In my synthesis report, I see that several signals internal to the microblaze have been routed onto the clock tree.
...
-2
votes
0answers
35 views
Digital Audio Filter: Delay, Echo, and Pitch Conversion [closed]
I'm using dsPIC Starter Kit (DM330011).
And I want to put those three stuff as a main functions.
Delay: when you speak on Microphone to record it and play it through speakers, hear your voice in 2 ...
1
vote
3answers
77 views
Custom USB Impedance question
I'm looking at making my own USB cable for a project. The primary issue I'm having is that I'm getting a lot of capacitance in my cable between D+ and D- (400ish pF) which is enough to throw off the ...
1
vote
1answer
74 views
Reason for certain steps in Circuit Analysis
The image is from this lecture.The instructor Prof. Shanthi Pavan says that the part encircled in orange can be replaced by a voltage source with current through \$v_1\$ as \$i_1\$ and not \$i_1 + ...
1
vote
2answers
61 views
Providing DC power with failover DIY for IP camera
I'm building a simple battery backup box for a 5V IP camera. I've got a few options for battery, sealed lead battery or a mix of portable LIPO style "USB" power bricks. I've seen boards built for ...
5
votes
2answers
98 views
What is the minimum temperature for FR-4 PCBs?
My company is working on developing a product that will go into commercial freezers, so my boss asked me to provide operating temperature specifications for the product. I can find "operating range" ...
-9
votes
1answer
65 views
Circuit Diagram Controller [closed]
I want to make a circuit diagram which will:
Read the speed of a servo
Divide the speed of servo
With the result of the division will be controlled the speed of an other motor like this: Servo ...
2
votes
1answer
54 views
should I use 2 SPI devices on Arduino UNO/PRO or 2 I2C devices?
I am using a microSD breakout board and the accelerometer ADXL345 https://www.sparkfun.com/products/9836.
each one alone works perfectly fine, but once I put both (sharing pins 11,12,13, but with ...
3
votes
4answers
326 views
why is wall voltage measuring 175V?
I was trying to use a DM-4100A multimeter to verify a power supply, and I'm not sure I'm using the multimeter correctly. The multimeter is >10 years old too, so maybe it is not working correctly.
...
0
votes
0answers
49 views
can power source damage electronics? [duplicate]
I think that this is a noob question but I just can't figure it out:
I have 2 devices :
First device working on 5V / 50A
Second device working on 5V/ 30A
I want to power them with power source : ...
3
votes
1answer
75 views
What do I need to know about leakage current?
I recently suggested a plan of removing one end of a resistor from a breadboard to remove it from the circuit in order to measure its resistance, but my mentor suggested that this won't work for high ...
-2
votes
0answers
24 views
Asic Ideas (FFT, AES, Motion Estimation) [duplicate]
Could you give me a list of applications with kernels that can be accelerated in hardware?
Some examples would include FFT, AES, Motion Estimation, Viterbi Decoder. I'm just looking for others.
I'm ...
1
vote
2answers
62 views
simple h-bridge polarity reversal
I am trying to reverse the polarity on a rather beefy motor (5 amp, 60v) in the most simple way possible.
I need to build an h-bridge just to reverse the current, I am controlling speed elsewhere. ...
-2
votes
0answers
36 views
Independant Contractor Electro-mechanical assembly charges [closed]
I have the need for a higher-level assembly technician that can build brackets, standoffs, and cabinet hardware as well as make and solder wire harnesses to boards and connectors. What is the hourly ...
5
votes
5answers
146 views
Stability problem in unity-gain opAmp
As a part of a controlled power supply for hardware-in-loop testing for a student driven project, I had to develop a current buffer (voltage follower) which could source up to 1 A.
I had the (bad) ...
0
votes
5answers
128 views
Good RS232-based Protocols for Embedded to Computer Communication
I'm working on a project that involves a good bit of data communication between a remote Arduino and a computer. The wireless connection is through a pair of XBees, so we have a RS232 link between the ...
0
votes
0answers
72 views
Compliance question
Q. You have +5 and +15 volt regulated supplies available in a circuit. Design a 5mA npn circuit source(sink) using the +5 volts on the base. What is the output compliance?
This is what I've done:
...
-1
votes
2answers
105 views
Power Supply Control Circuit
I have to build the circuit shown below as a homework, it is a power supply with frequent energy switching; but the schematic is incomplete... I should add another circuit which controls the voltage ...
-4
votes
1answer
49 views
What type of AT commands should i use? [closed]
I want to display my location information from a GPS receiver to a personal website(or any other website) using a GPRS modem connected to an arduino board through a USB host shield. My problem is ...
1
vote
0answers
47 views
How does zero balancing work in an amplifier? [closed]
I'm using an industrial amplifier which has coarse and fine balancing. I uploaded the circuit picture and circled the fine balancing in red. I use it to zero the output(for offset). It is done by ...
-5
votes
0answers
61 views
Applications with kernels that can be accelerated in hardware [closed]
Could you give me a list of applications with kernels that can be accelerated in hardware?
Some examples would include FFT, AES, Motion Estimation, Viterbi Decoder. I'm just looking for others.
To ...
2
votes
3answers
99 views
How exactly does switched capacitor system work, what exactly is the detail of the primitive that switches
I have been seeing these switched capacitor circuits for some time now and have even seen Z-transform being used to model how these circuits behave. While I can see that there is some capacitor that ...
0
votes
1answer
49 views
Should one use resistors to protect an mbed when using it to simulate keyboard key presses
One can use mbed to act as USB Host or as a USB Device. One use of the latter is to have it emulate a USB Keyboard by sending normal key presses. The general page on using mbed as a USB Device is in ...
0
votes
2answers
51 views
Make two bluetooth modules communicate directly?
Can one buy two cheap (and identical) bluetooth chips and make them talk to each other without needing a PC or a mobile phone?
I'm guessing the answer is a basic 'NO', but I might as well ask.
...
5
votes
3answers
142 views
Is it better to have a poor top layer copper pour or no copper at all?
For a few small 2 layers boards I'm doing, I'm using the top layer for parts and signals and a ground pour on the bottom layer with no or very short traces, based on comments and answers to my ...
2
votes
2answers
93 views
Are additional smoothing capacitors required off of a voltage regulator
This is a subset of a circuit I am building to run motors off a PIC 16F884:
simulate this circuit – Schematic created using CircuitLab
I noticed last night as I was drawing up my ...
1
vote
1answer
53 views
Multiplexing with or without transistors
I'm doing something in where I need to multiplex 6 7-segment displays. About doing it, I found things like this:
And things in where the same thing is done without the transistors, just by ...
-1
votes
0answers
40 views
Problem with impedance matching on DIY 4 pole 3.5mm audio splitter
I built an audio 4 connector 3.5mm splitter. The goal is to play a sound clip through a phone's mic input across a call, while recording the same sound clip on the computer. I used the TRRS ...
3
votes
1answer
36 views
SD Comms Resetting Processor
I have implemented an SD/FAT combination on a Renesas RL78/G13 processor. The SD card is being driven using SPI.
The code has been proven to work on two custom target boards using a 2GB card - the SD ...
-3
votes
0answers
72 views
Microcontroller, ARM, and FPGA [closed]
I'm going to study Wireless Sensor Network. I'm looking for a good way for understanding micro-controller, ARM and FPGA: i mean books, free technical materials available on the web, like university ...
1
vote
4answers
94 views
What is important in computer clocks' signal: signal edges or intervals when signal is stable? Will multiple value propagation occur?
I am trying to figure out some basics of digital electronics. We have all seen the squared graph of the computer clock signal:
I have read multiple articles on the Internet and still can't figure ...
3
votes
2answers
99 views
How good is coaxial cable?
My question relates to the accumulated AC voltage that will appear on the screen of a length of coax:
If the cable is properly terminated at one end and fed with data (or any signal) at the other ...
3
votes
1answer
50 views
Convert between dBA, dBV and RMS values
How do I convert between dBA, dBV and RMS values? For example, I have used a current probe (clamp) with a gain of 100mV = 1A to measure a series of currents in dB and I would like to know the ...
5
votes
2answers
166 views
Power Supply Design - Multiple Voltage Regulators
I'm trying design a benchtop DC power supply for powering small projects, breadboards, arduino, etc. This is a list of what I want from it:
Fixed voltage rails for 24V, 12V, 9V, 5V & 3.3V
Edit: ...
-1
votes
0answers
18 views
Interfacing MSP430 with a INT035TFT (TFT LCD) [closed]
I have a INT035TFT 3.5 inch TFT LCD manufactured by Displaytech ltd. I need to interface it with the MSP430-P1611 board from Olimex. The LCD already has an inbuilt display controller(SSD1963), so I ...
