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Questions tagged [design]

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

82 questions with no upvoted or accepted answers
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6
votes
1answer
657 views

Interfacing FPGA to an external chip and timing constraints

I have designed a system using Artix-7 FPGA on a custom board. The goal is to transfer 32-bit data to an external onboard chip whose data bus is an inout port. ...
4
votes
2answers
410 views

Managing reverse currents using MOSFETs

I'm planning to use a chip with two 5V output pins to provide power to two systems: a MCU (attiny85, operating voltage: ~2V - ~5V) and a USB device (input current: 3A). On top of that, I'll have an ...
3
votes
2answers
170 views

Why are project files in Altium modified every time they are opened? Is there a way to prevent this?

I use Altium Designer 18. When I open a project file (.PrjPCB), the asterisk ("*") appears next to the project name indicating that the project has been modified, but I haven't actually made any ...
3
votes
0answers
219 views

RF switch for multiple antennas

I'd like to design an RFID reader with 4 output antenna ports. My RFID reader's module maximum output power is 30 dBm. My target is for the maximum output power in the antenna ports to be 30 dBm. ...
2
votes
1answer
61 views

Help needed to select proper electric motor for constant drive

I need about 180 degree movement, back and forth in about one second. Maximum torque is about 2.2 kg ⋅ cm. I have tried RC-servos (up to 20 kg ⋅ cm), but they all burn within first 12h (maximum drive ...
2
votes
1answer
501 views

MOSFET Sizing in Wide-Swing Current Mirror Design Exercise

TL:DR How do I know how to size transistors? This is the same problem as this one. Now knowing that I can change L, I know that my W/L ratio to make Von = 200 mV is roughly 6.75. Also knowing that ...
2
votes
1answer
139 views

Synopsys Synthesis with underlying modules as gate libraries

I am trying to synthesize my Verilog modules into 1 top module which contains all the modules extracted into 1 top module. With setting -hierarchy option in write_file, I get all the modules ...
2
votes
2answers
731 views

MOSFET Amplifier: Maximum Signal Swing without Clipping

I have a degenerated common source amplifier. I want to know what's the maximum input signal I can apply before the output signal begins to clip. What I currently do is to increase the input signal ...
2
votes
1answer
150 views

Designing an efficient PSU

I am designing a PSU capable of producing 5 watts @ 5V 1A. The design will power about 12 RGB LEDs (totaling about 400mA @ 5V) and a audio class D 1.4 W amp. Space is no issue but efficiency and cost ...
1
vote
0answers
19 views

HFSS SAR anlysis Calculation

I am calculating The SAR anlysis on a human head of a wearable antenna that i have made . I have added a waveguide port and after simulation it does not show the radiation pattern using the HFSS ...
1
vote
0answers
112 views

Transformer/Inductor Bobbin Sizes

I have to design a 150 Ampere, 1.5 mH Inductor for a power supply project assigned to me, and off-the-shelf components are to be used. My instructor is insistent on using a transformer Bobbin to wind ...
1
vote
0answers
50 views

IoT wireless solenoid circuit

I am a Newbie and I do not have a lot of expirience. The circuit has been put together from pieces I have found on the internet. My goal is to develop a reliable wireless solenoid circuit to water my ...
1
vote
0answers
64 views

Laser Tag System Design Review

I have been working on a project to make my own laser tag gins and sensor vests. I have completed the electrical side of my design but this is the first time I have designed something like this and ...
1
vote
1answer
150 views

branch address computation single-cycle vs multi-cycle vs pipeline risc-v

I'm not sure about at which stage do the address computation take place at each of the versions of the risc-v? I just wanted to make sure i got that right- Single-cycle risc-v: Branch target address ...
1
vote
0answers
81 views

Fractal Antenna Design

I am trying to design a monopole fractal antenna using HFSS. My problem is with the excitation, I am trying to excite it with a connector with three terminals, where the middle terminal will be ...
1
vote
0answers
201 views

What do TA, TG and M mean on the scheme?

I have a electrical scheme but I can't get what do TA, TG and M mean? Can anyone explain me? P.S. I am a programmer, not an electrical engineer, so maybe it's a trivial question.
1
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0answers
59 views

Are GX12 connectors in common use? Is there another name for them?

I have a project where I need to send NeoPixel data from an RPI "base station" to a neopixel art project. Both the base station and the art project are enclosed already. Length is short, just a few ...
1
vote
1answer
55 views

How to optimze a coil for needed voltage?

Faraday's law for a coil is : V = A * M * N Where: V = Peak output-voltage A = Area of the cross-section of the wire M = Rate of change of magnetic flux in the coil N = Number of turns of the ...
1
vote
0answers
29 views

CST Studio Space State Matrices

I am new to using CST Studio and I am trying to figure out how to see the state space matrices (A,B,C,D) of a designed antenna to describe its radiation pattern in other software. Any help on the ...
1
vote
0answers
94 views

Are there commonly used equations for short-term overpower of wirewound resistors?

If I have a wirewound resistor rated for 250 W that might need to dissipate, say, 400 W for several seconds, is there a commonly used equation for finding its temperature rise or time to failure under ...
1
vote
1answer
233 views

Capacitive fluid level sensor design and insulation

This is a question regarding the measurement of a fluid level (in my case water) using a capacitive sensor. Capacitive sensors are a common topic, but I have one specific question: It is necessary for ...
1
vote
0answers
175 views

Is this stackable low RPM generator design viable?

I'm trying to invent viable hand-crank energy generator for charging phones and similar low-power appliances. I want to avoid gears altogether in the design, because they are hard to manufacture at ...
1
vote
0answers
73 views

Design of a differential pair

simulate this circuit – Schematic created using CircuitLab Problem: I need to design a differential pair with a gain of 30dB To make this design I have to used 4 mosfets transistor 2n7000 with ...
1
vote
0answers
92 views

Why short 3 terminals per contact on a membrane keypad?

What is the purpose of a three-terminal momentary contact in a matrix keyboard? The motivating example is that I have a damaged membrane keyboard where some of the keys do not work. At first I ...
1
vote
1answer
55 views

Creating a small range, small baseline varying resistor

I am doing a design project on making a passive varying resistor device. I have a flex sensor that increases in resistance when you bend it. It has a 10k ohm nominal resistance and increase to 110k ...
1
vote
0answers
223 views

OrCAD Allegro PCB Designer Ground Plane

i want to assign a black color to Ground Plane (GND 0), it's shape is polygon and it's color is gray like shown on below image, i have two questions: is this a possible polygon shape to implement ? ...
1
vote
0answers
107 views

ESD (and EMI) protect long slow lines

I'm designing a measurement and control board to interface with an old (70s) PLC. The board consists mainly of I/O ports, both analog and digital in- and outputs. To have my boards not fried by the ...
1
vote
1answer
51 views

Migration from multimode to single mode fiber

In my company we are using custom measurement systems with multimode fiber optic transmitters and receivers for synchronization between different devices. We are thinking of migrating our multimode ...
1
vote
0answers
281 views

Will this resonant IR2153 circuit work?

Will this work? Proposed principle of operation: R-C oscillator starts resonation of coil and capacitor. The R-C oscillator is overriden by the induced voltage. The frequency is dynamically adjusted....
1
vote
0answers
146 views

How to interpret LTspice simulation outputs for improving dual channel boost converter design using LTC3788

I am working on a boost converter design using the LTC3788. I would like to take advantage of the dual output capabilities of this chip to produce 24 VDC at 4 amps on one output and 48 VDC at 2 amps ...
1
vote
1answer
42 views

Cut off a circuit whitest charging a battery

I have a simple (analog) photosensitive circuit designed to turn on at night. My question relates to charging it. I need an easy, preferably cheap method to disable everything in the circuit whilst it ...
1
vote
0answers
2k views

How to produce electricity with mechanical power/spring coil

As a home project I want to make a electricity generator which uses a spring coil, which when turned/wound(just like the mechanism in wrist watches) enough times will start unwinding and generate ...
1
vote
0answers
489 views

Flyback Converter Design Help

I am unsure whether I should edit on my previous question or create a new one. Please give me your feedback on the proper way of doing it here.Back to the question, I have struggled for the past few ...
1
vote
0answers
2k views

Finding Values of Rd and Rs to satisfy the N-MOSFET design

I've been stuck on this design problem for a while and I am just filled with a lot of equations and unknowns and not getting anywhere with it. Here's a picture of the problem with the problem ...
1
vote
0answers
396 views

Piezo speaker driver not giving full differential voltage - why?

I am trying to drive a piezo speaker at 20kHz with maximum voltage swing from a 10V source. Previously I had used a square wave plus its inverse to give the equivalent of 20V across the speaker but I ...
1
vote
0answers
905 views

Designing a Multistage Amplifier

I have to design a BJT multistage amplifier to meet a specification provided by my professor. The first stage is to be a differential amplifier, and the second stage is to be a common collector ...
1
vote
0answers
992 views

Calculation for the Boot Strap capacitor

For design of a synchronous buck converter (which would be used to charge the battery) which would be driven by Micro-controller's PWM output, i selected the IRLB8748 NMOS Power transistors (for both ...
1
vote
0answers
961 views

how to simulate wide swing cascode current mirror

I want to design a wide swing cascode current mirror (question-left) and in order to apply Iref, I have designed a PTAT and applied it to M3 and M5. Iref must be 50uA and the diagram of output should ...
1
vote
0answers
177 views

Inverse engineering 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 ...
1
vote
0answers
601 views

Amplitude modulator for a sine wave generator

I have a home made, mostly using the design in a magazine article, radio frequency signal generator, and I would like to be able to modulate (AM) the sine wave output, which is up to 8 MHz, with an ...
1
vote
1answer
49 views

In this semi-ideal photodiode, what would be the physical interpretation of this current?

A real photodiode can be expressed as a circuit made of several ideal components, it looks something like this: simulate this circuit – Schematic created using CircuitLab I copied it from here ...
1
vote
1answer
224 views

STM32F103C8T6 custom design check

Following the failure of my first board design, I designed the following STM32F103C8T6 board. I only routed the fundamental parts of the board(MCU,caps, crystal, regulator etc.) This is a 2-layer ...
0
votes
0answers
87 views

Help me choose the communication protocols that I need

I am developing an industrial sensor using a sensor IC and an ARM MCU which communicate via I2C. The data size is 3 bytes. Because the environment in which the sensor is located is harsh ( high ...
0
votes
0answers
39 views

Quadrax routing on a PCB

When connecting twisted pair wires to a printed circuit board, I hope I am right in thinking that differential pair routing is used on the board in either a stripline or a microstrip configuration to ...
0
votes
1answer
34 views

How to choose the correct fuse in a double paralled battery supply system?

Suppose I have the following system: simulate this circuit – Schematic created using CircuitLab As you can see we have: Two 500V battery with an estimated 500mohm average internal resistance. ...
0
votes
0answers
27 views

Design Bootstrap Follower

I got confused in the emitter follower circuit with tracking feedback (bootstrap). The mechanism of operation is understandable, but how do I choose the resistor values ​​correctly and optimally? For ...
0
votes
0answers
121 views

What is the function of CLKREQ and PEWAKE when those are used in PCIE?

I could understand The CLKREQ# signal is used by the L1 PM Substates mechanism. And PEWAKE signal is used to wake up the ROOT COMPLEX(RC) during the sleep mode. And these two signals are bidirectional ...
0
votes
0answers
78 views

Switch to use in high g-force environment?

I need an on/off type switch (spst) on a device that will be subject to high, continuous centrifugal force loads (500-1000G or 5000-10000 m/s2)). Will your everyday, off-the-shelf switch handle this? ...
0
votes
1answer
141 views

Multi channel Mosfet driver ghosting between channels (with suggested fix)

I´m pretty new to the forum (as you will see by my limited electronics knowledge) and I have a wierd problem when trying to control some automotive fans at variable speed. The fans each have an ...
0
votes
0answers
34 views

Learning designing a Arduino pcb, doubt about USB traces

what consideration should I have for the USB section. How do correctly the usb traces? What means this curves? This is my reference schematic and due board. Thanks