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H: Will a regular neodymium magnet attract an electromagnet not currently being supplied with power?
I have a setup for one of my robotics projects where a neodymium magnet is placed across from an electromagnet. I power the magnet with DC through a L298N motor controller that is connected to an Arduino.
Will my neody... |
H: Input impedance of emitter follower
I decided to calculate the input impedance of the following emitter follower circuit as a practice.
I used this well-known small signal model for the BJT:
For voltage gain, I obtained
$$A_\text{v}=\frac{v_\text{out}}{v_\text{in}}=\frac{\beta/r_\pi-1/R_\text{B}}{\beta/r_\pi+1/R_... |
H: How does I2C handle data loss?
Does I2C have any data loss prevention mechanism? If so, how does I2C recover?
AI: I2C has several mechanisms to prevent data loss:
multi-master collision detection and arbitration
ACK/NACK after each byte
clock stretching (slave slows down the master)
SMBus adds a couple of enhance... |
H: Should I place ferrite barrel/ring on my Nokia 5110 module data lines?
I have Nokia 5110 LCD module from AliExpress. My motherboard is ruled by ATmega64A and control pins for LCD are grouped together as pin header (male, 8 pins in total). The module itself is placed on the external side of plastic case and will be ... |
H: Fault Ride Through requirements for wind turbines
First a short introduction: (the question is below the first image).
The capability of fault ride-through of wind turbines is the most important requirement related to national grid codes. Based on that, wind turbine should remain connected to the network during var... |
H: DC -DC buck converter W/o PWM signal( kind of)
Hey so i'm new to electronics and I've tried constructing a buck converter (using software only) circuit without the use of an external PWM source (microcontroller, 555 circuit) and i came up with this (steps down the voltage from 12 to 4.75 V using a p-MOSFET whose ga... |
H: What is this schematic symbol? (Circled B with four diagonal hatches)
(It's not on the wiki page for electronic symbols, or this sparkfun page with lots of symbols.)
AI: The symbol is for a lamp (with rays of light eminating from it).
The 'B' is, most likely, for 'blue'. This would be typical for an industrial mac... |
H: Powering an op amp from a Reference voltage?
Let's say I had a low power op amp (pre-amp stage) going to an ADC (LTC2412).
My question is: If I wanted a super precise, low noise, low TC drift, positive supply line could I just power the +A5V line from a voltage reference IC like the LTC6655LN-5? My circuit only ne... |
H: Piezo connected to ESP32 - Why doesn't it kill the input?
I have a ESP32, and a piezo disk connected as a sensor:
Piezo - to GND
Piezo + to Analog In
50K Resistor in parallel to piezo
My understandin is that the piezo generates a voltage when it is mechanically deformed either through vibrations (like sound) or t... |
H: Store byte instruction in RISC-V assembly
I have a short snippet of RISC-V assembly that I'm having trouble understanding. I'm not sure if I'm interpreting the instructions wrong, from my interpretation it seems as if the branch (BNE) will be taken but it is given that it should not be.
Given commented code:
000001... |
H: ESP32 - Read multiple analog inputs
I need to read multiple analog inputs as fast as possible on a ESP32. With as fast as possible, i mean that ideally all inputs are read simultaneously.
Currently I simply read them one after the other with consecutive AnalogREAD() calls in my code, but it happens that I read a va... |
H: Custom D Flip Flop in Logisim Simulation Error
I am building a custom D flip flop in Logisim as a part of the project for my computer organization course and I am not allowed to use the built-in flip flops. When I designed this flip flop everything went well and every wire and connection was green and there was no ... |
H: Emitter follower as single-ended power amplifier
I have seen that the following circuit is mentioned as a single-ended class A power amplifier.
Also, push-pull configuration is mentioned as a better power amplifier, which isn't single-ended, and has two transistors in emitter follower configuration.
Can't we use o... |
H: What will be the transfer function of the block diagram?
I have tried it for hours but I am not getting the correct answer.
Here is the link to the question: https://ibb.co/gFhrwCW
Here is the link to my attempt at solving it: https://ibb.co/GcMZC13
AI: You should probably attack it this way (a helping start): -
O... |
H: How does an operating system or program detect the CPU model name?
What kind of binary compatibility is present for 2 processors sharing an Instruction Set?. I had asked a question on Computer Science Stack Exchange, to which I got an answer which said:
As a trivial problem, you can write a program that will try t... |
H: when does induction machine supply capacitive power
Can an induction machine whether it being a motor or a generator supply capacitive reactive power?
AI: A motor or generator consists of coils. Therefore, the voltage coming from the motor/generator will mainly be inductive reactive power. |
H: Can you just rely on battery BMS's undervoltage protection for normal use
Let's say you buy a lithium battery with BMS circuit included. The BMS protects against undervoltage (and other things) and only 2 wire-leads come out of the battery (so no seperate charging wire). eg. Lithium battery.
Is it okay to use this ... |
H: What kind of terminal block is this?
I've perused a few resources (linked below) trying to learn more about this strip / block, but they mostly have side views / cross sections. I just want to know what the things in this picture are called so I can replace them -- starting with the parts of the terminal block / st... |
H: How do I choose series resistor for stacked Zener diodes?
I have 12-30V input, and I need ~10V and ~5V. So I feel like an easy way to do this would be to stack 5.1V Zener diodes front-to-back and have taps for both of the voltages I need. Something like the image below. But, I'm having trouble determining the appro... |
H: 4-wire fan controlled by potentiometer and 555 IC not behaving properly
Here's the schematics:
Forgive me for the newbie schematics. This is the first time making one.
I used an LMC555CN IC and this Delta BFB1012VH-5D84 Blower Fan (Can't find a datasheet for this one).
I can control the fan with the potentiometer ... |
H: Induction motor with reversing stator magnetic field
The question:
The answer:
The strength of the torque depends on the difference in speed between the stator's rotating magnetic field and the rotor's rotation. The larger the difference in speed the greater the induced voltage, current and torque.
When the motor ... |
H: Using an RGB TFT screen on the Raspberry Pi 4
I want to use the HT0700EI02A TFT screen on the Raspberry Pi 4 Compute Module.
Raspberry Datasheet: https://datasheets.raspberrypi.org/cm4/cm4-datasheet.pdf
Screen Datasheet: https://cdn.ozdisan.com/ETicaret_Dosya/623388_201461.pdf
Apparently, this screen uses a p... |
H: Understanding battery capacity measurement circuit
I came across this battery capacity circuit on the internet and it seems interesting and useful. So I would like to build it myself. However, I don't fully understand the working of some of its parts so would like to learn how those work.
Forgive me if some of my q... |
H: BJT As a Switch. Efficency?
I needed a 2 digit display for a project and simply ordered a device 1, without the proper thought. To be fair I have learned a few things about 7 segment LED displays. Unfortunately I got one which is a common anode type, rather then a common cathode, for which there seem to be plenty o... |
H: Purpose of Bus to Bus Entry (Kicad [Eeschema])
On the far right of Eeschema, there is a button below Wire to Bus Entry: Bus to Bus Entry.
What is the purpose of this, and how can it be used?
AI: It serves no purpose other than a 45° aesthetic. It has been removed in KiCad version 6 and replaced with a bus element ... |
H: Getting the energy consumption in joules over a period when having current and voltage
I'm trying to calculate the energy consumption over a period of 1.3 seconds in joules (J).
I have a sample every 100 ms (0.1 second) with the current and voltage (in volts) (in practice, the samples have a much higher granularity... |
H: Drained 12 V car battery jumping another car
I was jumping another car with a 12 V car battery and it jumped the other car. However, it seemed to kill the 12 V car battery in my car and then I couldn't start mine. I used a multimeter and found out that the battery only had about 9 V left in it. Can someone explain ... |
H: Alternative clock generator for CDCE62005 reference clock?
I am working on a circuit which uses the CDCE62005 to generate clock signals for a DAC and an FPGA.
The evaluation board of the CDCE62005 uses a PE7745DU-30.72M for the primary clock reference - but I can not find that part anywhere.
Is there any similar pa... |
H: Trouble Understanding Dual Transistor Flashing Circuit
I am having trouble understanding how this circuit works. I've breadboarded it out and the LED flashes but I can't seem to wrap my head around how the NPN vs the PNP is creating the flash. Any help is greatly appreciated!
Schematic:
simulate this circuit – Sc... |
H: Photonicinduction - Less Turn Equals "Same Amps" but "Less Voltage"
I was recently watching a video by the youtuber ‘Photonicinduction’ and I came across this video.
When the video was at 1:50, I noticed that there were 4 Turns on the primary and secondary so its a 1:1 Transformer.
The cable he is using is 400mm po... |
H: Question regarding serial in serial out shift register
I started learning serial in serial out shift register today as below picture.
I have a question but can't search the reason behind on internet. As an example, when input "110" is connected to a serial in serial out shift register with 3 block below, it need e... |
H: Motor power, torque and RPM importance (simulator steering wheel)
I would like to build a DIY racing simulator steering wheel very similar to this one.
My question is, how will the specifications of the motor used affect the experience at the wheel after the pulley system?
I understand torque is easy to manipulate ... |
H: How to get a single pulse for 10 milliseconds?
I am trying to get a single pulse of 10 milliseconds on the output of my 555 timer. I following is my schematic:
I am supplying 12 V for Vcc. The value of Resistor R and capacitor C is 100 ohms and 100 microfarads.If my trigger switch is pressed and let go, I get a 10... |
H: Opamp delay off circuit check (updated)
I have a relay that I want to have a 3 second delay switch off from when a pressure switch (normally open) returns to the open state. When the pressure is below a certain level the pressure switch closes, once the pressure has reached the set level the switch opens.
I've buil... |
H: OPA344NA op-amp MEMS Mic
I'm planning on getting Audio Data from a MEMS Analog Microphone with an OPA344Nna as the OP-AMP.
I'd like to just make sure the audio circuit looks correct.
(Analog/Audio is something a bit new to me, but I'd like to get it working for wake words / other)
I'm planning on taking readings us... |
H: Can't connect to STM32 chip
I have soldered a STM32F103VF chip (LQFP100) on a breakout board, which I want to connect to via my ST-Link (clone). However, ST-Util (and STM32CubeProgrammer) cannot connect to the chip.
MCU Datasheet: https://www.st.com/resource/en/datasheet/stm32f103vf.pdf
Picture of the setup:
Pinou... |
H: Clipping when using a CD4051 analog multiplexer
Regarding the CD4051 analog multiplexer,
Data Sheet
If I connect VDD to +5 V and VSS, VEE to GND. The analog signals are coming from modules with the analog signal having a DC offset that can be as low as -300 mv.
Does this analog signal pass through the multiplexer a... |
H: What is this chip in a switching power supply marked 1ADJM?
I'm trying to identify a chip, possibly a switch, used in a switching power supply.
It's 6-pin, and marked 1ADJM (or maybe IADJM)
AI: It is MP1470 step down converter from MPS.
Datasheet here. |
H: How to implement SPI SCK with ESP8266
I have a ESP8266-01 and a Microchip 23LC1024 memory chip which communicates via SPI bus, and I want to drive it using the ESP8266-01. My thought is to implement the SPI protocol in software i.e. bit-banging. My concern is about driving the clock signal in very specific timings.... |
H: Measuring AC voltages with battery-powered oscilloscope
I'm wondering if I can view only for few seconds the waveform of a small transformer on my DSO.
It can handle up to 800V according to the manual (transformer outputs are 100V maximum.) From what I know, connecting the DSO to an AC voltage will make the BNC con... |
H: Why does the number of holes in an N-type semiconductor increase with temperature?
I was watching this video.
I understand that the dopant atoms introduce huge numbers of free electrons that essentially overshadow any additional electrons that break free due to higher temperatures.
What I don’t understand is why t... |
H: How does starting torque increase by increasing rotor resistance?
As the formula below shows that the torque is both directly and inversely proportional to the rotor resistance. However, since it's inversely proportional to the square of the resistance, it is the predominant relation.
Increasing the rotor resistanc... |
H: Can MOSFET withstand the ESD from drain when a TVS diode is installed between gate and source?
Assume that an N-channel MOSFET is used.
A TVS diode is inserted between gate and source.
The source is connected to GND. (Not real grounded (not earthed.))
The drain is open and connected to the external connector.
conn... |
H: How do you calculate power loss for a diode?
For example, the DSB20I15PA Schottky diode datasheet mentions a threshold voltage of 0.23V and a slope resistance of 7.2mΩ.
I need to calculate the power loss at different voltages, as the battery drains. e.g. 14V down to 10V.
Is it as simple as subtracting 0.23V from yo... |
H: Why I haven't 0V when I put 5V in my cmos
When I Have 5v in my cmos, usually my NMOS have to be close and 0V, however there is a residual tension, I use MbreakN3 NMOS in PSPICE.
I don't think this is rd resistance because youtube tuto use it and it works.
Thank you
AI: That's not a valid CMOS circuit.
The P-FET i... |
H: Common grounding between two microcontrollers
I am trying to get two microcontrollers to communicate. One is a Tiva-C TM4C123GH6PM (3.3 V.) The other is an Arduino (5 V.) I will use UART.
Should the grounds of the two microcontrollers be connected to each other? Why is a common ground needed?
AI: Why is a common gr... |
H: where to place registers in VHDL modules
I'm a software guy by trade and I have been dabbling in digital design on FPGA using the open source toolchain. I have made a few designs and generally understand how the handle verilog and VHDL.
One of the things I'm wondering is not really a black and white question but ra... |
H: Low frequency transformer core material
For the first time of my life, I am trying to do a low frequency transformer. I’m used to seeing low frequency transformers built with, what I think to be, laminated silicon steel.
I have some difficulties to find a graphic which compares low frequency core material in functi... |
H: Arduino EMF detector / non-contact voltage detector
I am trying to build an EMF detector or non-contact voltage detector based on an Arduino to be used as a prop. The detected EMF value should be read from an analog input and based on the level, 1-5 LEDs should light up. I found two circuit designs which didn't loo... |
H: Why is this dynamic microphone grounded / wired with more than the two pins? is it important?
I am rewiring a dynamic microphone that does not require any phantom power (also wicked simple no off / on), and I noticed, when I only wire the two wires to two of the three pins it still works and seems to sound great.
W... |
H: 8051 timer delay calculation
In the following program
MOV TMOD, #01H
HERE: MOV TLO, #0F2H
MOV THO, #0FFH
CPL P1.2
ACALL DELAY
SJMP HERE
DELAY:SETB TR0
AGAIN: JB TF0,AGAIN
CLR TF0
CLR TR0
RET
It is asked to calculate the time delay generated by the delay subroutine.
Clearly the counter or timer counts a total of F... |
H: What components would I need to receive SMS-CB messages?
I could simply use a LTE modem for this (with a SIM Card). But since SMS-CB is an FTA (Free-To-Air) signal, having to buy a SIM card for this (I know, it's not expensive) would be overkill.
I am specifically looking to intercept EU-Alert/NL-Alert CB messages,... |
H: AC circuit working principle
When a power source is AC (alternating current) one is a phase and the other is neutral.
Does phase and neutral lines change their polarity over time or only phase line voltage and current up and down sinusoidal form? Which one is correct? If it is not changing the polarity, how do rect... |
H: Can't turn on NMOS when using 1M pull-down resistor on gate
I am using ATmegA328P MCU to control ignitors which need about 500 mA current to work. To provide such current, I use AO3400A N-MOS to control the ignitors. In early design, I didn't use pull-down resistors. The N-MOS can ignite ignitors when MCU outputs 5... |
H: Math behind pull-up resistors
I have a question about the the math behind of pull-up resistors and how they work. I don't have any experience in the Electric Engineering field so it's probably a basic question.
I saw many explanations regarding WHAT pull up resistor is doing but rarely HOW it is doing it.
Consider ... |
H: What happens when we reach the maximun atenuation in Optical Networks Terminals (Optical fiber )?
Let´s suppose We have the following Optical Network Terminal :
According to datasheet, the receiver sensitivity is : -27 dBm
Now Let´s suppose We have the following fiber optical network :
As we see , the Optical Po... |
H: Synchronous DC-DC buck converter I saw online
I constructed this synchronous buck converter circuit I found online and I wanted to know how reliable it actually is: ( I used a battery source for the VCC+ pin on the op-amp because the 12 V line was too noisy for some reason); also, I've seen people say that the buck... |
H: How does a half-flash ADC work?
Specifically:
Why does the first 4-bit ADC output the 4 MSBs? Say an input value of 8 corresponds to an 8-bit output of 0000.1111, where 0000 is the MSBs and 1111 the LSBs. If that same input value of 8 enters the first 4-bit ADC, that ADC has to output 1111 - and that is the LSBs o... |
H: Printing or "Stamping" a Transistor
I've looked around at quite a few websites to see if it is possible to make a transistor at home. I found that recently they have successfully "printed" nanocellulose using an ink jet printer (https://hackaday.com/2021/05/12/3d-printed-transistor-goes-green/). However, I doubt th... |
H: Why the "Extra" Diode in this DC Motor Driver?
I've been shown this circuit, which uses a MOSFET to allow a 5V signal (from an Arduino Uno) to drive a 5V DC motor. I know that diode D1 is a flyback diode to protect the motor when it turns off, but what is the function of diode D2?
EDIT: I misspoke; D1 protects th... |
H: Optocoupler Package Markings
I have a 4PIN dip octocoupler that’s cracked on the board of a power supply I’m fixing.
The markings on the optocoupler are
CT
817C
953K
What does the 953K mean? Is it a manufacturing batch number?
Thanks in advance!
AI: According to CT817C datasheet from CT Micro:
9 = Fiscal Year
53 =... |
H: Recreating Arduino UNO - PCB design (How are the components connected?)
I'm trying to recreate the Arduino UNO in order to be good at PCB design via EasyEDA or Altium. I have recreated the Arduino Uno schematic and design but it is hard for me to figure out few things (please refer to the image.)
Why are those pa... |
H: How does this "single-ended push-pull with transformerless driver" work?
I'm studying the circuit block below in an Italian textbook, "Dispositivi e circuiti elettronici", by M. Gasparini, D. Mirri.
The circuit is called "single-ended push-pull with transformerless driver".
Without giving any comprehensive explana... |
H: Unexpected voltage from my H bridge
I have a problem with my H bridge. I don't understand why I have -1V insted of 12V or -12V.
AI: According to comments bellow my post, I use power mosfet and it works, I assume that it depends of internal resistance.
I use BSP171 P-MOS and power_mbreakn. |
H: Combinatorial loop of SR latch
I implemented an SR latch in Verilog.
module sr_latch(
output Q,
output P,
input S,
input R
);
nor(P, S, Q);
nor(Q, R, P);
endmodule
However, Xilinx ISE reports a warning:
WARNING:Xst:2170 - Unit sr_latch : the following signal(s) form a combinatorial loop: n0000.
... |
H: What does the integrator do in a Delta-Sigma converter?
This question is in reference and an extension to this earlier question: How a Delta-Sigma Modulator Works. The role of the integrator was discussed in the comment section but I'm not following at all.
In the first and initial cycle where I input 1.015V and t... |
H: At t=0 the voltage across the Inductor will immediately jump to battery voltage. Why?
While reading transients i come to read......
"the voltage across the inductor will immediately jump to battery voltage (acting as though it were an open-circuit) and decay down to zero over time (eventually acting as though it w... |
H: How to read timing diagrams: ak4554 audio serial interface
As a newbie I struggle to understand interface timing diagrams of AK4554.
I am asking this particular example but I believe your answers will enlighten me about how to read any timing diagram.
It is a audio DAC, and here its datasheet: http://www.akm.com/a... |
H: How to calculate the maximum current rating of an ammeter manganin shunt?
I want to make a shunt for an ammeter using a manganin wire. I don't know how to chose the wire diameter for the desired current. For example, my shunt will have 0.05 ohms and it must withstand 5A for a continuous usage and 10A for short peri... |
H: Unexpected output from TPS73633 LDO
A while ago I had some trouble with a TPS73633 (see Troubleshooting handsoldered TPS73633 SOT-23 LDO whose output is unexpectedly high) . I didn't get the 3.3v output voltage that I was expecting, whatever I tried. Since I wan't sure whether the error was in my board design or so... |
H: Choosing Vds and id values for a Power MOSFET
I have a question regarding the choice of an appropiate power MOSFET in relation to the circuit below. What are the safety margins that I need to look for.
For example, Vdd = 100V and I = 5A. Obviously, buying a transistor with Vds = 100V and id = 5A is not a good idee... |
H: uA702 OpAmp internal circuit confusion
I know that i don't have to understand the internals of Op-Amp ic to be able to use it but it's just some curiosity.
Anyway i've found this file have some explanation of the ic internals "through the ages".
I came to this very first circuit and there's something i really want... |
H: Can Blackfin DSPs boot from 'any type' of SPI external flash?
So I'm working on a project that contains a Blackfin processor, specifically the BF592 datasheet
One thing that confuses me is how exactly the boot up process will work. During development, I plan on loading programs through the JTAG interface. This will... |
H: HVAC heating control with thermostat, on/off or continuous?
I have a honeywell rth8580wf heating thermostat.
I wonder what the output of the "white" terminal is (heating control).
Is it only going from 0V to 24V or is it continuous depending on the room temperature?
AI: It's a contact closure. When the thermostat w... |
H: Drain current of NMOS circuit is constantly changing on DMM
Hello I am working on a lab that pertains to the IV characteristics of n type MOSFETS.The lab calls for recording the value of the drain current while increasing VDS/VGS from 0 to 6 volts in steps of 1 volt.
I constructed this circuit
As I increase the... |
H: Positioning of the stabilizing capacitor for the ESP 12
I have been researching the ESP 12, and I am ready to hook it up. Because the Wi-Fi uses high current, it has been advised to add a stabilizing capacitor across the Vcc and ground terminals of the ESP 12. These are on opposite sides of the ESP 12.
I am wonder... |
H: Secondary voltage referred to the primary
I am studying transformers and I am not completely understanding a basic detail, but it is annoying me.
When we draw the equivalent circuit of a transformer, why is the secondary voltage referred to the primary written as \$V_{2}'=\frac{N_1}{N_2}V_2\$ ?
AI: These currents -... |
H: Electronic component that detects angular rotation like a potentiometer, but endless and digital
I am relatively new to this whole scene but am wanting to start a small project sending midi-signals from a board I am creating.
That said, I am a big fan of these endless, smooth digital potentiometers for example buil... |
H: Help identifying a connector where wires are directly inserted into "slots"
My question is fairly simple.
Would you be able to identify this type of connector:
I can't seem to find it anywhere.It's not supposed to need any kind of crimp (wire is inserted inside as shown in the picture).
AI: It looks like this conn... |
H: Arm mode and Thumb mode makes the PC's bit 0
The ARM and Thumb modes are word-aligned and halfword-aligned. I understand this means that if it's in ARM mode, the start of addresses must be divisible by 32, and if it's in Thumb mode it has to be divisible by 16. But how does this relate to the PC's bit 0 never used ... |
H: What happens when we connect two generators in parallel with a single load?
I read that in large utility systems more and more generators are added to provide extra power. I'm lacking some basic knowledge here. So, what happens when we connect two generators in parallel? Is it like connecting 2 voltage sources in p... |
H: What happens when we connect two identical batteries in parallel with a resistance R?
I read somewhere that the voltage stays the same(it will be equal to the voltage of one of the batteries) but the output capacity increases. What does this mean? Will the current in the resistor increase?
Applying superposition t... |
H: How to add a 32-bit input in Quartus 2
Can you help me to add a multiple pins input in Quartus 2? If there is not a default one, how can I add it by MegaWizard Plug-in Manager? Thanks!
AI: I presume you are meaning in the Quartus Schematic?
If so, just change the name of the input (or output or bidir) to whatever[3... |
H: Why does the stator field rotate at the same speed as the rotor field in a synchronous generator?
In the case of the induction motor the rotor never catches up with the rotating field of the stator because if it did the induced voltage would be zero as there is no relative movement between the rotor and the stator ... |
H: Why doesn't the LM7805 circuit short circuit?
I'm new to electronics and have made some simple projects using a LM7805. I'm using the following schematics:
I don't understand why this circuit works. Why doesn't it short circuit? I thought electricity always takes the "easiest" path which in my opinion would be the... |
H: Finding voltages in a circuit with no power supply
I´m trying to solve the following circuit
However I cannot understand how is possible that E2 and E1 have voltage if there is no visible power supply on the circuit. What´s the approach to solve this circuit?
AI: E1, E2, and ground are the visible voltage.
You hav... |
H: Manually storing the stack pointer rather than using push and pop (Assembly)
What will be the instruction sequence that implements PUSH R4?
A: SUB SP, SP, #4
STR R4, [SP, #0]
B: STR R4, [SP, #0]
SUB SP, SP, #4
C: ADD SP, SP, #4
STR R4, [SP, #0]
D: STR R4, [SP, #0]
ADD SP, SP, #4
E: All of the above are possible... |
H: Accidentally connected an Atmega328p and an Atmega644p to 12v instead of 5v. Are they screwed? The 328 seems to be bricked, the 644 seems fine.
I'm working on a project using the Atmega328p and Atmega644p, so first I built myself a USBasp programmer board for each one and I've successfully programmed a blinking LED... |
H: Turning on/off leds very fast. Will it do harm?
I am using an arduino board to controll a led strip. 3 transistor and 3 resistors are between the board and the leds. 1 for each color (RGB). I am using analogWrite to change the brightness.
But I wanted to make the leds even less bright, without adding another resist... |
H: Atmega1284P-PU - how to connect more than one device through SPI?
I need connect 3 modules via SPI with ATMEGA1284P-PU. I looked on datasheet, but I found only one SPI.
On which pins are other SPI?
AI: You can use several modules using the same exact pins. The trick is to not let these several devices work at the s... |
H: 25A USB port blew up a TP4056
I have made a bench power supply from an old PSU and added a USB port connected directly to the 5V rail (leaving the data pins disconnected).
When I connected a TP4056 charging board (like this), the TP4056 smoked and blew up.
I am trying to understand if the board was defective (or I ... |
H: Purpose of bare copper perimiters on HF PCBs
I have seen many RF PCBs with a thick, rounded area of exposed copper going all around the PCB, like in this example:
My intuitive thought is that this is for some kind of grounding or shielding can, however I have seen this on PCBs that had none of that.
What is the de... |
H: Why does stator current increase with increasing load in a synchronous motor?
Isn't the current, coming from the 3-phase source of the stator, constant? We don't change the source, so how does the current change? Is a voltage induced because of the magnetic field of the rotor?
This leads me to another question whi... |
H: What humidity sensors allow the user to configure their I2C address?
I'm building something that will need to use eight humidity sensors, and I want to use I2C to communicate with them. However, all humidity sensors I've found either have a fixed I2C address, or sometimes they have an address pin to choose between ... |
H: In an AM radio do the electromagnetic waves cause the antenna to resonate to produce an alternating current?
Looking at Hertz's original experiment with electromagnetic waves with the spark gap how did he know how to build his antenna size to receive the wave that generated the spark ? In what way is the AM antenna... |
H: Switching input to instrumental amplifier with an analog mux (ECG, EEG)
I'm trying to find a cost effective method of taking samples of electrical signals of the body (and potentially plants).
Can you have one high precision instrumental amplifier and then use an analog mux to read different inputs (different elect... |
H: Charging cells in series and parallel
I am looking into a electric vehicle charging system and using a cell that can charge at 1.6 A and a voltage of 4.2 V. Therefore I believe the max power I can expose this cell to while charging is:
P = IV = 1.6 * 4.2 = 6.72 Watts
Would I be correct in thinking that if I were to... |
H: Steady state response
Could you explain me please what does this question exactly want me to find? Or, how should I start solving ?
AI: To solve this you need to:
Calculate impedances of circuit's branches (note there is pulsation of voltage).
Calculate RMS values of voltages. (ad. 1-2 use complex numbers).
Solv... |
H: Determine the I and V of a logic gate
I have got this problem in my text book.
Determine V and I of the following circuit:
The result is I = 4mA and V = +1V (ideal diode)
How can I solve it using assumption process? Please help me out.
AI: I assume you use the ideal diode model, i.e. for positive currents the volt... |
H: Is it 'normal' to use a DSP's internal timers to generate lower speed clock signals for audio codec sampling?
I'm currently working on a project that features a Blackfin BF592 processor (datasheet).
I'm trying to interface this DSP with a stereo audio codec (datasheet).
Originally, I assumed that this audio codec w... |
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