The process of creating electronic products, including components and end-user devices.

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load cell platform

We are making our own platform for our digital weighing scale using a load cell(maximum capacity of 200kg). We have made something like this but we are unsure if this is the most ideal design ...
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46 views

Replace crystal earpiece in bat detector circuit

I've been following the instructions on http://pw1.netcom.com/~t-rex/BatDetector.html which includes the following schematic for a Frequency Division Bat Detector circuit: The instructions clearly ...
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1answer
35 views

Designing and simulating a common source amplifier circuit

This is the problem: And this is my design for R1 and R2: So, using B2 Spice simulator I made this circuit according to the design: Vin_ and Vout_ are voltmeters. But the problem is that ...
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1answer
58 views

Buck converter design problem/confusion

I have problem with designing buck converter. I have tried to design it by using instructions from this site: Buck converter And here are my parameters: V input - 72V max V output - 12 V ...
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61 views

selecting analog design or digital design [closed]

Generally speaking, what are the motivations that people to go with analog or digital design? Which one is harder to specialize? Which one offers more average to specialized designer? In future ...
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1answer
51 views

JK Flipflop design for conveyor project

I have a small project/problem I am working on. While running a conveyor belt continuously with items on it, I need to stamp every other item. I am using a photocell to detect if an item is ...
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1answer
53 views

PSPICE Simulation of Cascode Amplifier Not Working

Can anyone please tell me why I am getting the following "floating node" errors. I have fiddled around with the resistors to see if it affects anything, so these are not the actual values. I have also ...
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96 views

Inverse enginnering time

I got this circuit from an automatic lightbulb sensor , it basically turns on whenever the IR sesnsor detects movement, I was able to reverse engineer the entire circuit, however this clever bastards ...
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38 views

Common Drain Design Not Meeting Spec

I am trying to design a Common Drain amplifier with specifications below. I have reworked the problem over 10 times now and have not achieved anywhere near an appropriate solution. I have spelled out ...
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1answer
133 views

Please rip apart my circuit design

I am making an opensource automated wireless window blind controller. It uses a motor to open and close standard metal blinds. Below are links to the project documentation: Full project page ...
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2answers
69 views

How to make an external PCI adapter that runs on USB3.0?

Motivated by old PCI (NOT PCIe) cards, and laptops without expansion slots, I want to try making a PCI-over-USB 3.0 solution. This is about 70% experimentation, and 30% actual use. Is this viable? I ...
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3answers
77 views

Enclosing/Casing Design for electronics (electronic eng. vs industrial designer)

I have been wondering, this since i dont have that much experience in product design, but, who is supposed to do the case design of an electronic product? the industrial engineer or the electronic ...
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4answers
1k views

How do you determine how much flash/RAM you need for a microcontroller?

Let's say you are starting an embedded project with some known functionality. When you select a microcontroller how do you select how much RAM you need? Do you use a developer board and code your ...
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1answer
43 views

Spread spectrum 400 KHz

I got a 6-phase DC-DC converter. Fsw=400 kHz, synchronization by external clock(CPLD). I need a spread spectrum 400 kHz. What's the best way? All chips what I've seen before worked on MHz and above. ...
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51 views

Design considerations for internal PC parts

I'm designing a PWM fan controller. It will be interally mounted inside a PC and will take power from the normal 4 pin Mate-N-Lock ("molex") connector. The on-board MCU and LCD will draw power from ...
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1answer
54 views

Pogo Pins for 1.5mm Pitch Test Fixture

I'm working on a design and am going to source a smaller pcb and solder it to my design. Before using the sourced board I'm wanting to test it and so I'm trying to design a test fixture similar in ...
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52 views

How can an ASIP design be implemented in hardware at low cost?

Imagine, I have created an ASIP (Application-specific instruction-set processors) design in the IDE, have done the tests and in simulation, it works well. Now I want to test it in hardware. But it ...
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2answers
96 views

Looking for a huge circuit compilation [closed]

I have noticed that during my circuit design i always end up finding around the net better ways to improve my designs pic related its an example, Its a fuse blown indicator that gets improved by ...
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32 views

Can I power a IOIO-OTG board with the regulator on a Koala Protoboard?

I'm building a small device which uses a IOIO-OTG board. I figured I would mount my components on a Koala Protoboard along with the IOIO to use the recharging/usb regulator circuit provided on the ...
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93 views

Design a Mealy FSM that functions as a sequence detector, generating two outputs y, z in the following way:

Initially both inputs are set to 0. Output y is set to 1 when the sequence "10" has been applied to the input x; output y should then be reset to 0 and y should continue detecting next occurrence of ...
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77 views

How to learn circuit design if I already know some circuit theory [closed]

I'm a recently graduated electrical engineer, but my curriculum never focused on electronics, besides the standard introductory level courses. I specialized in telecommunications and I mostly work on ...
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1answer
52 views

Implementing F using a demultiplexer and an extra AND gate

Use a 1-to-8 Demultiplexer and an extra AND gate to create the function: F(x,y,z) = ∑m(1,3,5) If I were using an OR gate I think this would be trivial, simply put the 1 3 and 5 ...
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2answers
168 views

How does someone initially design a digital system for HDL?

So I have really been hitting the example code hard this week in an attempt to better understand some HDL design basics, specifically FPGAs with VHDL. The book I am using (if anyone is interested) is ...
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69 views

Tango PCB Designer

i'm trying to run the old Tango PCB on a DOSBox, on windows 8.1. I did the same things to make it run that i did on windows 7, but it's not working on windows 8.1, have anyone tried to run Tango on ...
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1answer
74 views

I'd like to improve this design to support ICSP

I'm new to electronics and this is my first circuit. I have some questions about implementing ICSP in this design. This is a bit of a long post with quite a few questions so I'll apologize in ...
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2answers
44 views

Karnaugh map: mirroring tables

When creating a map for n variables, we have to do (n-1) mirrorings. I wonder, why are the variables assigned in the way you see it on the picture. How do I know, when expanding a map, where to place ...
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1answer
52 views

Switching power supply using faraday cage and EMI protection?

Several switching power supplies in the market use this kind of cages to protect the circuit, however, i have this question, A) Is this used as a faraday cage due to the high frequency used by it? ...
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58 views

Smartphone headset jack to relay [closed]

Looking to see if anyone has seen a relay triggered by a sound file played thru the phones headset. My idea is to connect an old smartphone to my home's WiFi and then connect it to my garage door ...
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1answer
53 views

Automatic cut off after switch is pressed

I have a fun one for you. Here is my diagram: It's a 555 timer in a monostable one shot configuration. What I want to do is find a way to prevent the LED from staying on if the switch is held down. ...
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1answer
59 views

Modify MEMORY component to more sensibly Load/Store value?

I have created the following electrical circuit using Logisim: My ALU takes in 2 8-bit values and performs the operation set forth by the [Op Setter]. In particular, when the [Op] code is [100], ...
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1answer
105 views

Connect ALU to CPU in Logism Circuit Design and output to 7-segment Display?

I've been playing around in Logisim to get some experience in designing basic electrical circuits. While I'm sure not the best, I was able to put together a functional ALU: 1-Bit: This ALU is ...
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83 views

Possible to copy a circuit from 1 Logisim .circ file into another Logisim .circ file?

I'm using Logisim to experiment with Electrical Circuit design, and I was wondering if it is possible to copy a circuit created in 1 Logisim .circ file and place it into a different Logisim .circ file ...
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87 views

Amplify a 12 MHz sine wave

I need to take a 12MHz AC sine wave, from around 3.3V - 10V @ 10uA, output 50V, @ 1A (or more). I have the signal generator for signal input, but I am not certain what I need for a circuit to step ...
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48 views

Passive Filter Negative Insertion Loss

Can someone please explain to me how a passive filter could possibly have a negative insertion loss? In the attached picture, this can be seen in the C or D curves where the insertion loss dips below ...
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1answer
2k views

Design a 3-to-8 Decoder Using Only Three 2-to-4 Decoders

Using only three 2-to-4 decoders with enable and no other additional gates, implement a 3-to-8 decoder with enable. The inputs of the resulting 3-to-8 decoder should be labeled X[2..0] for the code ...
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1answer
65 views

How to explicitly connect hidden pins in eagle?

I am working on a project where I used a shift register 74HC595N which has hidden GND and VCC pins in Eagle. So I used the invoke property as shown in the pics, and connected the VCC and GND to the ...
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1answer
72 views

OLA adder and signed digit vhdl design problem

I have implemented the following online adder for signed digit using vhdl code and I have simulated my design according to the example table shown in the figure attached the problem is I am not ...
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3answers
79 views

concept for true random number generators

I have an idea. Lets say we have an unpowered TTL set-reset flip flop with both inputs tied to 5v(logic high). When we apply power to the flip flop, it goes into a quiescent state, so there is no ...
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1answer
272 views

Antenna Design for specific directions

I am designing an antenna for a device and was hoping to gain some insight in the correct design direction for the antenna. The Idea: A receiver & antenna that fits in a 6" diameter by 3" deep ...
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3answers
126 views

How to determine how much current and or voltage a given circuit “needs”?

My apologies in advance if I make any wrong assumptions. Say you have an outlet that is rated at 120V and 10A. My power adapter for my MacBook says it is rated at 16.5V and 3.65A max. How was it ...
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1answer
48 views

Using a digital signal to turn on and off a vibrating motor

I'm designing a circuit with the IOIO-OTG board and a vibrating motor. The idea would be to have a digital pin on the IOIO board control the state of the motor (either ON or OFF). The motor operates ...
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2answers
63 views

Building a first State Machine circuit - Technical Help

I just learned how to synthesize a diagram of a finite state machine into a diagram of a logical circuit composed of D flip flops, a clock and logical gates. However, I don't really have much ...
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41 views

Trouble getting push button working in Nios II

To give you an idea of what I'm trying to accomplish, the 18 LEDs on the board are to scroll right to left, then back to the right, and keep looping as such. Where the push button comes into play is ...
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77 views

What can I do with Cadence OrCAD software?

As the question says, what can I do with the Cadence OrCAD software rather than PCB design and schematics? I didn't understand what the Cadence website is saying. I just downloaded Cadence OrCAD 16.6 ...
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1answer
90 views

CadSoft Eagle polygon won't reach pads in Molex library

I'm using the Molex 5569 library in CadSoft Eagle. When I create a polygon, it won't reach the pads at all. The problem occurs only with components from this library. Have a look at this screenshot ...
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1answer
50 views

How can I trigger other circuits based on specific values of a 12 bit ripple counter?

I've built quite a few circuits but I've never really designed anything from a "schematics first" approach. Mostly just tinkered with designed and code until I got it right. Now, I want to build a ...
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93 views

Choosing the right capacitor

I have been told that in order to not damage a battery is better to connect it to a capacitor, to deliver current in a smooth way. This is because we are using a circuit where a peak of current is ...
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1answer
133 views

MOSFET H-bridge design

given the circuit below to be used as a H-bridge with AVR PWM. Is this a good desing to use? What can you recommend? I already built something like this but without the resistors. ( and so burned ...
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1answer
105 views

BJT Topologies - Design Principles at RF

Here are some rules of thumb I've learned when designing single-transistor BJT amplifiers: High input impedance is good Low output impedance is good Biasing resistors should draw ~10% of the ...
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3answers
220 views

custom FPGA PCB Design tips

I am planning to design a custom FPGA PCB. the PCB will contain sensors. I need to read the output of the sensors and process them in the processor. I have completed many projects using FPGA's, but ...