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SPI Clock Signal not stable

I am probing the SPI Clock pin 13 with my analog discovery 2. Nothing else is connected. The clock signal is there but it rises over time. (see picture) Here is my code: #include <SPI.h> void setup() { // put your setup code here, to run once: SPI.begin(); SPI.beginTransaction(SPISettings(100000, MSBFIRST, SPI_MODE0)); pinMode(8, OUTPUT); } void […]

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How does Power Over Ethernet classing work?

In this POE controller there is a table about how to set up classification of the device. I think i understand the concept of classifying PD devices, its to tell the the supply equipment the power demand the PD needs. But there are a few scenarios that im not sure what will happen why there […]

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Voltage Limitations of a header being used as a voltage selector

I have an application that takes a reference voltage. These voltages could be considered ‘low voltage’ as they range from 0 to 1000 V. Below is a reference schematic of what I’m trying to accomplish, demonstrating with two input voltages: simulate this circuit – Schematic created using CircuitLab The idea is that I use a […]

Categories
Arduino Ask Engineering

SPI Clock Signal not stable

I am probing the SPI Clock pin 13 with my analog discovery 2. Nothing else is connected. The clock signal is there but it rises over time. (see picture) Here is my code: #include <SPI.h> void setup() { // put your setup code here, to run once: SPI.begin(); SPI.beginTransaction(SPISettings(100000, MSBFIRST, SPI_MODE0)); pinMode(8, OUTPUT); } void […]

Categories
Ask Electrical Engineering Engineering

How does Power Over Ethernet classing work?

In this POE controller there is a table about how to set up classification of the device. I think i understand the concept of classifying PD devices, its to tell the the supply equipment the power demand the PD needs. But there are a few scenarios that im not sure what will happen why there […]

Categories
Ask Electrical Engineering Engineering

Output of the 555 pin 3 high when power on

When I turn on power of 5V of 555 timer, the pin3 is always goes high in the very first power apply. Can we fix this issue? I need the pin3 not goes high when power on, until I make the pin2 goes low. Does anyone have this same issue? How to fix it?

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Do surface charges exist when EM wave gets reflected by dielectric boundary?

If both the materials on a boundary are dielectric then do surface charge exists. I was solving using pillbox it showed that there should be surface charge on boundary to satisfy change in normal component of Electric flux density vector. But I am confused how so can happen.

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STM32L053R8 – Bare metal LED issues

I’m following a bare metal course, I have managed to set up the project within IAR, my project compiles and runs. I’m attempting to get the user LED (LD2) to flash before I continue the course. I’m operating on a NUCLEO board with the STM32L053R8 chip. Trying to manipulate the chip registers with this User […]

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Amplifying a minuscule signal without external power source?

I recently came across this circuit : http://sgitornado.altervista.org/diyirig.html I tried to understand it, but I have several questions I can’t really search for, as I’m an amateur and don’t know the terms or what I am looking at exactly. I don’t understand why the circuit starts with such a small capacitor; doesn’t this mess with […]

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Stove igniter producing electric shock

I have a canon cooking range. When I push igniter button, it’s body gives electric shock. What can be the reasons and how can I minimize the risks of getting those shocks?