All Questions

0
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0answers
4 views

How does an ARM MCU Run faster than the external Crystal?

So before this I only worked with simple 8Bit atmel MCU's and I realized on my development's board schematics it has only a 12Mhz crystal. yet the MCU operates at up to 100mhz. (I think the default ...
0
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0answers
3 views

Making lavalier microphone with Esp8266-07

I'd like to make a lavailer microphone and receiver using two Esp8266-07 Wifi modules.I'm using condenser microphone with it's own preamlifier using 5V.I want to compare my signal with 300kHz triangle ...
0
votes
0answers
3 views

STM32 RTC with HAL libraries

I am working on stm32l053 (nucleo 64) and I want to track time with integrated RTC. Since I am quite new to stm32 development I am using CubeMX and HAL libraries. My problem is that the time is not ...
-1
votes
1answer
21 views

9 volt battery and a 10 watt IR LED

I connected a 9V battery to a 10V IR led and the brightness lasts 3 seconds before "dimming" down to a soft glow. How do I maintain the initial brightness? Do I plug in a few AA or do I buy a 30 or ...
0
votes
1answer
17 views

VI component tester not working good when capacitor is placed parallel with diode

I am trying to repair mainboards with VI component tester. (such as this device and that device)I check the characteristic VI curves of the components on the card and identify the defective parts ...
0
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0answers
18 views

Complex Boolean Algebra simplification problem

Anyone has a solution on how to continue this simplication? \begin{align} X &= \bar R \bar S \bar T \bar u + \ldots \\ &= \bar R \bar S (\bar T\ldots)+ \ldots \end{align}
0
votes
2answers
22 views

I2C Communication Between STM32F3 and SSD1306

I am trying to write data to my 128x32 OLED display. I researched it online and found that it has the SSD1306 controller connected to the display. It uses the I2C protocol and it only has 4 pins (VCC, ...
0
votes
3answers
28 views

analysis of BJT PNP type - why they can use voltage divider?

Hi everyone, I try to understand why some books used in a voltage divider to find the Base Voltage? or maybe the right question is HOW they can use voltage divider if there is base current? what I ...
0
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0answers
17 views

What’s the disadvantage for solving 5 variable Kmap using overlay and reflection method?

As far as I know solving kmap using Gray code is widely used but is there any disadvantage in it?
0
votes
2answers
22 views

Power rating of a UPS

I find it odd that manufacturers specify power rating of Uninterruptible Power Supplies (UPS) in VA instead of Watts since VA doesn't tell you how big of a load the UPS can supply. A case in point is ...
0
votes
1answer
18 views

GAN FET gate current requirement

I'm looking for advice in making sure the FET driver I've chosen is capable of driving the FETs I've chosen with turn on time as low as possible. I'm going to use the LMG1210 and EPC2020 with 12V ...
0
votes
1answer
31 views

CPU architecture

im very new to CPU architecture! I wanted to ask, what is the Data memory component in the image below, is it writing/reading to and from RAM or Cache? And also what is the sign extend used for? I ...
2
votes
3answers
29 views

Is there a down side to setting the sampling time of a SAR ADC as long as possible?

In configuring the sampling time for the internal ADC of a micro-controller (STM32F446RE) to sample the output of a current sensor connected to a PWM controlled motor, the sampling is triggered at ...
0
votes
1answer
32 views

What is the cost of converting 12V (lead acid battery) to 220V and back again to power 12V appliances?

I have a small house measuring ~ 8m x 4.5m. It is in Indonesia and power outages are expected daily. Probably the daily power outage is on average less than half-an-hour, but sometimes the outage can ...
5
votes
3answers
46 views

Placing bypass capacitors after VCC reaches the IC

I have a question about bypass capacitors and their possible placements. I am designing what I hope to be a double sided PCB, which has the VCC and the vast majority of the data lines on one side, ...
0
votes
3answers
44 views

Short Circuit Question

I know that static electricity can damage components, even if it does not destroy them or “break them” studies and tests have shown that it could decrease performance even a little if no noticeable ...
1
vote
0answers
13 views

Questions on types K Map

What's the disadvantage of Overlay K Map vs the Reflection K Map and vice versa and what's the differences between these two
1
vote
1answer
32 views

Linear Regulation Concept Confusion

I was watching one of Jacob Baker's videos (http://cmosedu.com/videos/f10/ece5472/lec1_ece5472_video/lec1_ece5472_video.html) At minute 19:30, he explains the concept behind linear regulation: His ...
0
votes
3answers
52 views

int functions with no return statement

In a course I am taking on embedded systems, I program LPC1768s which are based on ARM using C. The main functions are always of int return type. However, there ...
0
votes
0answers
14 views

Interfacing with tft lcd(ILI9225) via SPI

As an exercise, I'm trying to make a driver for ILI9225 TFT LCD using SPI. (This one https://www.amazon.com/HiLetgo-ILI9225-176x220-Support-Arduino/dp/B00LSG5HI0) I consulted a datasheet of ILI9225 ...
5
votes
1answer
180 views

An overseas company is making a machine for me and they need to know whether I want 1,2 or 3 phase and what voltage

I'm in Quebec and the company making the machine is in China. The machine is an industrial sized T-Shirt sublimation machine that does two sided printing. So there's a large heated plate that is ...
1
vote
1answer
30 views

General open license PCB GPS antenna

Is there a basic passive GPS reference antenna design that would be considered fair-use or "free to use" that can be placed on a PCB as a strip antenna or patch antenna? I'm looking not to violate ...
0
votes
1answer
29 views

Low power 100MHz sinusoidal modulation laser driver [on hold]

I am looking for a low powered laser driver which can modulate pulses at 100MHz sinusoidal. Is this possible, something that you have come across or possible to custom design. I am looking for ...
0
votes
0answers
20 views

Which power supply choose for lineal actuators?

I have two actuators each of them with the following characteristics: 16 inch, 12v, load 750 N, travel speed 10mm / s, duty cycle 25% BUT Current Draw is not specified, and I have no access to the ...
0
votes
0answers
10 views

How do you properly install backup power delivery? [migrated]

I have a backup power bank made of an inverter and car batteries. It charges when the grid power is on and turns on when the grid power turns off. However, my "electrician" repurposed the grounding ...
0
votes
3answers
32 views

VF Parameter in a Transmission Line

For a lossless line, you have \$Z_0=\sqrt{\frac{L}{C}}\$ and \$VF=\frac{1}{c\sqrt{LC}}\$. For a line with R, L, G and C parameters, we have \$Z_0=\sqrt{\frac{R+j\omega L}{G+j\omega C}}\$. But how ...
0
votes
1answer
15 views

Relationship of Slip and Angle Between Rotor and Stator Flux for Induction Motor

I know how slip and flux angle individually affect torque of induction motors but I can't understand the relationship between slip and flux angle in terms of torque. Do they both have different effect ...
0
votes
0answers
33 views

X Ray Transformer with Full Wave Rectifier Design

I current am in possession of a center tapped X-ray transformer that can supply 80 kV and 10 mA. However, I need this transformer to supply approximately 0 to -37 kV DC at around 8 mA. In order to ...
5
votes
2answers
283 views

Is this resistor leaking? If so, is it a concern?

I found this resistor on the control board of an old Whirpool washing machine: Is that fluid leaking from the resistor? (Why would that happen?) Could it be something like stray epoxy or a chemical ...
0
votes
0answers
21 views

USART6 STM32F746NG isn't working

I'm having trouble configuring the USART6 in my STM32F746NG. I am setting up the USART6 to enable UART comunication, using the code below to initiate it and also create an echo function. ...
0
votes
1answer
56 views

What are the differences between triacs?

I need to replace a broken BT134-600E triac. I found out it's 600V 4A sensitive gate triac. Which of the following triacs can be used to replace the original one and why? MAC97A6 MAC97A8 BTA16-600B ...
-1
votes
0answers
35 views

Turn on led-strip parts using arduino [on hold]

I am software developer and I am starting my electronics adventure, so I have a very basic knowledge. As a first project I am thinking about arduino and led-strip. I would like to split led-strip to ...
0
votes
1answer
57 views

Why does the current in MOSFET have a quadratic function (explain logically without using the integration method)?

The current equation relating Vds ,Vgs and Vt is already known to us ,but if there is any way we can find out how it varies quadratically without using the formulae?
0
votes
1answer
57 views

What are laser diode drivers used for

When do you need a laser diode driver to power and pulse a laser diode? Is it related to the power it needs or the speed of the pulse? I am looking to use multiple laser diodes which have an output ...
0
votes
1answer
19 views

Fringe field effect: calibrating vs guard electrode

Which method is more effective at limiting errors associated with the fringe field effect when performing a liquid conductivity measurement, using a guard electrode or using a reference liquid to ...
0
votes
0answers
30 views

stm32F401re ethernet shield unable to associate IP address

I bought STM32 F401RE and Ethernet shield HR911105A with MCU W5100. I'm not able to configure simple connectivity with it. I have setup all SPI wires and simple code for setting up IP, subnet, and ...
0
votes
2answers
27 views

USB LPT Converter by FT232R

I am really green and even greener in these topics, but i am trying to create a project which will be converting lpt signal to usb signal via FT232RL. I was searching a lot in internet and i have some ...
1
vote
1answer
16 views

Does the 969973-3 SMD receptacle need mounting holes?

I am designing a board that uses a 969973-3 wire-to-board receptacle. In its drawing there are specified six 1.2 mm (mounting?) holes. Does anybody know what are they used for? I've seen pictures ...
0
votes
1answer
30 views

Kirchhoff Voltage Law in a two port network

In a tutorial about h parameters of a two port network, I find the below snippet in the image unable to grasp. According to KVL, the total voltage in a loop is the algebraic sum of the individual ...
0
votes
1answer
64 views

What are these soldered/un-soldered dotted-shapes? on the traces which don't have soldermask?

Please look at this image(see the soldered/un-soldered dotted-shapes which are identified by arrows). This circuit belongs to a laptop adaptor. What are these soldered/un-soldered dotted-shapes? As ...
1
vote
1answer
32 views

Why is recombination rate in an intrinsic semiconductor proportional to product of number of mobile electrons and number of holes?

I know that when an electron falls into a hole the number of mobile carriers reduces to zero from two. And when an electron jumps into conduction band the number of mobile carriers increases to two ...
0
votes
1answer
35 views

How to recognize an OTG USB port on an embedded device?

Sorry for the noob question, I'm trying to flash a new firmware on a tv box with rk3066. The datasheet says that the chip has OTG capability but there are 3 usb ports on the board and I can't tell ...
0
votes
1answer
23 views

Inferior limit of output voltage in op-amp low-pass inverting amplifier circuit

I'm simulating the low-pass inverting amplifier circuit using LTSpice: I put a sine of amplitude 4 as input to see the behaviour of the op-amp in the non-linear zone. I was taught that the output ...
2
votes
3answers
218 views

Simple fuzz pedal using breadboard

Complete newbie here. I've been trying to reproduce a simple fuzz pedal using breadboard. Here is the scheme: And here is the current state of my breadboard: The only sound I hear is white noise ...
0
votes
1answer
51 views

Circuit Diagram with only NAND Gates

I need confirmation that the following circuit diagrams are correct for their Boolean expressions. I've been told that each logic circuit must have a MAXIMUM of 4 NAND gates, however, I cannot manage ...
2
votes
4answers
178 views

Why are these traces shaped in such way?

Please look at this image(see the PCB traces within the circles). This circuit belongs to a laptop adaptor. What are those parallel soldered-traces on the PCB traces? Why aren't they soldered to ...
2
votes
1answer
81 views

What will be the real voltage along the line with a voltage source and a capacitor?

Take the following circuit: If I do a simulation of this circuit I get this graph: The strange thing is that in the simulator it gives the same voltage sine wave in the circuit, near the voltage ...
0
votes
2answers
28 views

Surge arrester placement in substation

Is it enough to place surge arrester on the terminals of the transformer in a substation, or every power line entering the substation should have its own?
0
votes
1answer
49 views

Is it possible to measure phase margin with the loop closed?

Everything I read on the web, concerning this question, says that in order to measure or set the phase margin of an amplifier the loop must be opened and the phase lag around the loop measured when ...
-2
votes
2answers
35 views

What technologies are used to fabricate gas sensors?

Different types of gas sensors exist. Sensors that work with light or resistance sensors. In general, what technologies are used to build sensors?

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