All Questions

12
votes
0answers
533 views

What is causing this long tail in the transient reponse?

I have a fifth order transfer function for which I designed a controller using pole-zero cancellation technique on a root locus. I am after <5% overshoot and <2s settling time. Currently, the ...
10
votes
0answers
225 views

Switch from JTAG to SWD with bitbang sequence on STM32F103VB

I am trying to switch from JTAG to SWD without any external devices. Why? Because I would like to use the SWO pin to send a stream of logging information to another device. To accomplish this ...
7
votes
0answers
3k views

Stability factors of a voltage divider bias circuit

I am trying to derive the stability factors of a voltage divider bias circuit. I could derive S,S', however, I'm facing some problem with the derivation of S''. Please help me in this regard. How to ...
6
votes
0answers
131 views

Microstrip transmission line impedance calculation

I'm attempting to calculate the necessary trace width of a PCB transmission line in order to have a characteristic impedance of 50ohm. However, different online calculators are giving me slightly ...
6
votes
0answers
388 views

LM386 guitar practice amp circuit not working, need help finding mistake

I'm very new to electronics and I built this guitar amp circuit on a breadboard: and it was working really nicely. Now I've decided to put the circuit on a universal PCB which I'll use in the actual ...
6
votes
0answers
528 views

Electric fly zapper - how is this safe?

My trusty electric fly-zapper broke, so I opened it up to have a look in case it was something simple. I have to say I was a little surprised by what I found inside: the capacitor reads 473K, meaning ...
5
votes
0answers
87 views

Contact a very small area (impedance matched)

In my current project, I want to apply a voltage to a capacitor (top electrode on a thin film heterostructure) very rapidly. Since capacitors have their own charging rate \$(\tau = R \cdot t = R \cdot ...
5
votes
0answers
203 views

Mazzilli flyback driver mosfets keep failing

I've been trying to build a high voltage generator consisting of a high-voltage transformer and a Cockroft-Walton multiplier. I have actually tried several different drivers to drive a high-voltage ...
5
votes
0answers
504 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
0answers
47 views

Can somebody please explain to me the principle of a T-T Earthing system?

How are the transformer, consumer's side and the generator earthed in a T-T Earthing system? I seem to understand that the generator and its frame should be earthed separately; The neutral of the ...
4
votes
0answers
62 views

Radio module resetting when fluorescent tube switched on/off

I have a PCB powered by an IRM-30-12 power supply (230VAC to 12VDC). On this PCB, I have a MRF24J40MD from Microchip and a Udooneo to drive it + a 5VDC regulator and the 3.3VDC of the Udooneo. After ...
4
votes
0answers
138 views

How to identify SMD device marked LEFBV?

I have a SOT23-3 component marked \$\underline{\textrm{L}}\,\underline{\textrm{E}}\,\overline{\textrm{F}}\,\overline{\textrm{B}}\,\textrm{V}\$ as shown in the following images: The following ...
4
votes
0answers
67 views

VHDL Procedure - Same variable for input/output parameter

I've written a component where I use the same variable for the input and output parameter of a procedure. A reduced example looks like this: ...
4
votes
0answers
76 views

Subthreshold Analog Accelerator - How is current derived through two sub-threshold transistors in series?

Was browsing the following paper: Fick, Laura, et al. "Analog in-memory subthreshold deep neural network accelerator." 2017 IEEE Custom Integrated Circuits Conference (CICC). IEEE, 2017. When I ran ...
4
votes
0answers
177 views

High-Level Synthesis (HLS) vs RTL for ASIC flow

I'd like to know when it's a good idea to use HLS over RTL (Verilog/VHDL) design if I'm targetting ASIC implementation? Can synthesis tools like Design Compiler convert HLS C/C++ into gate-level ...
4
votes
0answers
91 views

Frequency locking for averaging resampling

Background I've done a long one-shot measurement of a periodic signal by an oscilloscope. Thus, I've captured around 250 periods of a signal. The signal itself is a pseudo-random binary sequence at ...
4
votes
0answers
374 views

4 switch Buck-Boost, boost not reaching designed current

I am working on a power supply that regulates the voltage coming out of a 3S LiPo battery. The buck portion of the circuit works fine and outputs 5+A with acceptable ripple. The Boost portion instead ...
4
votes
0answers
125 views

Incrementing net name for group

I am wanting to make 50 copies of the block below, but I need incrementing numbers on each of the net labels (these will go to a connector). I do not want each block connected to the other blocks. It ...
4
votes
0answers
148 views

Help with deciding my layout for EMC tests and SI. Different alternatives

I am thinking of what way would be the best to layout my system in order for it to have the best SI and pass EMC tests. My system consists of two PCBs joint by a flat flex cable (up to 7cm) and these ...
4
votes
0answers
3k views

UART reception problem when SysTick Interrupt is enabled

I'm using a STM32F411RE-Nucleo board and generating a project with Cube MX for System Workbench. The problem is that HAL_UART_Receive function doesn't receive input ...
4
votes
0answers
230 views

Setting up T2080 to FPGA PCie DMA

I'm doing an FPGA design using a T2080 MPC interfacing to an Altera Cyclone V FPGA. The goal is to use my FPGA to pump 2 other FPGAs on the same board. I need to create a scheme that allows the ...
4
votes
0answers
135 views

imx6q sabre board microphone

I have been trying to record audio using the circuit below. It is different from the normal microphone circuit in that the MIC_IN and MICBIAS are separate paths. I tried to connect an electret ...
4
votes
0answers
193 views

Home made passive tablet pen

I have an old wacom tablet at home, its really big and I'd like to use it but I've lost the pen for it. It uses pens with passive LC circuitry. The board creats an EM-field (I can see it on my ...
4
votes
0answers
113 views

Testing strategies for testing a Scheduler

We have developed an in-house Scheduler which is based on Rate-monotonic scheduling. We have 6 tasks (5 actual tasks and 1 idle task). Our scheduler works on 1msec timer interrupt. Before sending it ...
4
votes
0answers
3k views

Dual active bridge converter

I'm having issues calculating the power losses associated with the operation of a bidirectional isolated Dual Active Bridge DC/DC converter. The converter is controlled using Phase Shift Modulation (...
3
votes
0answers
75 views

Is this symbol standardised?

Sometimes there are these two half-arrow symbols on PCBs and on enclosures. See the images, for examples. Those symbols are often placed near the screws, that are to be unscrewed upon disassembly. ...
3
votes
0answers
45 views

Frequency Divider Analog Circuit issue

I am trying to implement a divide-by-two circuit quoted from the book "Low power CMOS circuits : technology logic design and CAD tools" by Christian Piguet Could anyone advise about the spice error "...
3
votes
0answers
68 views

Inrush Current problem?

I have a 360W 36V Switch Mode PSU which I am using in a garden lighting system I have designed. I'm in the UK so it's running off 240V therefore can supply about 10A. Each section of the ...
3
votes
0answers
40 views

Abstract signal and noise model for a logarithmic image sensor

A conventional grayscale image sensor pixel can be modeled as a "light bucket." Photons arrive on the sensor pixel for a fixed exposure time. The light bucket fills up with photo-electrons linearly ...
3
votes
0answers
65 views

What is the difference between input and output offset voltage for an opamp?

Looking at many OpAmp (and InAmp) datasheets, I find the info either confusing or lacking. For example, in one datasheet they just call something Offset Voltage ...
3
votes
0answers
99 views

ADC conversion value spike during ADC conversion

Description of the situation I am trying to get an analog vibration sensor signal to a Raspberry Pi 3 B+. To convert the analog signal to digital values, I'm using Waveshare High-Precision AD/DA ...
3
votes
0answers
65 views

Switching regulator not suppressing variance in input?

I am having a little problem with my switching regulator, based on a AP65211A and here is my schematic: Parts: ...
3
votes
0answers
30 views

MOSFET pinchoff reduce current

I understand that in an n channel MOSFET as Vgs increases, electrons are attracted towards the gate forming an n channel. These electrons are responsible for the conduction of the MOSFET. As Vds ...
3
votes
0answers
35 views

7030 SMD LED pad configuration

I have not done a lot of work with SMD LEDs and have a question about the pad layout. I have done quite a bit of research and haven't found much helpful info yet. I am working with 7030 SMD LEDs ...
3
votes
0answers
92 views

Find transfer function and step function for this circuit

Can someone help me to find the transfer function of this circuit (i want to have the tension through the capacitor I think) and the step response in order to get the voltage in the function of the ...
3
votes
0answers
97 views

Weird problem on STM32 ADC with Interleaved Mode

I am sampling a signal on the STM32F3 Discovery board (stm32f303vct6) with two ADCs working in interleaved mode. It works great with a 200kHz 1V sine wave. But when I apply 10kHz 100mV sine wave, I ...
3
votes
0answers
43 views

Advice for a Solar Charger and Battery Project

I am a high school robotics teacher (no formal engineering training) and I am taking a group of students to Kenya this summer to work with high school students there. The organization we are ...
3
votes
0answers
55 views

Detrimental impact of magnetic field on PCB and battery?

We are developing a small consumer electronics product consisting of a small 4-layer PCB along with a few PDM microphones and BLE chip/ an antenna, as well as a LiPo battery. We are locating a small ...
3
votes
0answers
82 views

Orientation of “bipolar” capacitors on PCB

I've come across a video on a popular and well-respected electronics channel on Youtube where they say that even bipolar capacitors have a preferred orientation in a circuit that minimizes hum and ...
3
votes
0answers
58 views

Power use question for a trail camera

I am trying to calculate how long that a trail camera can be deployed before the batteries run out. The trail camera in question is a Reconyx HyperFire 2. Here is a useful review of the trail camera ...
3
votes
0answers
46 views

Microphonic SAW transmitter?

I built this very simple SAW transmitter, with a simple "spring" antenna for the right frequency. To test it, I tuned a portable receiver to around 433.92Mhz and fine tuned it until I heard silence. ...
3
votes
0answers
88 views

How to distribuite high current in multilayer PCBs

I'm designing a 150Amp controlled rectifier and I'd like to know how to distribute the current using a multilayer design. Currently, I have a 4 layer design containing: Top Layer: 6oz, Vdc+ and Vdc-...
3
votes
0answers
55 views

Alternate uses for Gate Driver - Driving a Load without External IGBT or FET

What issues would one encounter by using a gate driver IC to directly drive a load instead of using it to drive transistors? For consideration would be the very affordable Infineon 2EDN752x series ...
3
votes
0answers
62 views

Can I extrapolate battery power by a brief observation?

Part of the research we are conducting requires us to estimate how detrimental our proposed algorithm to the battery life of the wearables. To do so, I opted to simply charge the wearable to 100% and ...
3
votes
0answers
87 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
82 views

Modeling scalar control of PMSM

I have met with a scalar control algorithm for a permanent magnet synchronous motor. I haven´t heard about it before so I decided to develop a dynamic model to further analyze this control algorithm. ...
3
votes
0answers
76 views

How to select a diode for baker clamp?

What are the requirements when selecting a diode for baker clamp circuit? 1- for example, How the reverse leaking current of the diode affects the circuit? can a diode with relatively high reverse ...
3
votes
0answers
56 views

System of multiple conductors: image method

The problem statement, all variables and given/known data The following figure represents the traversal cut of a system with two cylindrical equal conductors of radius r0 length l at a distance d ...
3
votes
0answers
204 views

SPI comunication - Only receive 0xFF (Linux)

I've been stuck in setting up the SPI communication in Linux and can't figure out any solution. I working with a beagle bone black, which runs Linux. I have a piece of code that send data through the ...
3
votes
0answers
166 views

Gate of a transistor and mosfet damaged

In my schematic, I found that the base of transistor Q7 (2n2222) was damaged. I tried to replace it with a BS170 MOSFET, and the same thing happened where the gate was damaged. The microcontroller ...

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