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H: wall warts: constant specified current though universal input voltage?
How come the input drawing current be constant (1.5A) even though it shows that the adapter is universal input (100-240V)? I mean that the power supply voltage varies in different locations still how come the current be same.
AI: The input curre... |
H: What is a RTOS, is it embedded or do I need to install? (MSP430)
First of all, I have the basic knowledge in low-level programming of microprocessors but I don't have the in-depth details which I need. I have never worked with RTOS before in my previous class. Now my thesis advisor wants me to test if a RTOS is rea... |
H: Why does putting resistors between Vcc/SDA & Vcc/SCL in I2C result in a square wave?
I'm trying to understand why placing resistors between Vcc and the data/clock lines helps my waveform be square, when I'm communicating between Arduino and an EEPROM chip. If resistors are not placed in the circuit, the waves look ... |
H: "mapping voltage" on an analog potentiometer using a voltage divider
I'm working on a simple project to learn electrical circuits. I built a little sound box that will play tones when you press buttons.
The battery provides 3volts and the "power boost" is a buck converter that increases the voltage to the 9v need... |
H: Switching RS-485 bus
As shown in the graph, I'm trying to use mcu-controlled switches to turn a segment of rs-485 bus on or off (so that only one segment is on at a time). I was considering analog switches but I'm not confident how to take care of the negative voltage.
My question is:
Is an analog switch the best... |
H: What is the difference between a 0 Ohm Resistor and a piece of wire?
As I was browsing through parts listings for a 3D printer project, I stumbled upon a resistor listed as "0 Ohm". Fittingly, it had a single band in the center: a black band. Because of \$U_t=R_tI_t\$, this piece immediately felt rather silly to me... |
H: wifi baseband access
I've got an unusual use case (optical communications) that would benefit from access to the wifi baseband signal before it is upconverted/modulated at 2.5Ghz. However most modern wifi chips combine baseband encoding and transmission encoding/transceiver functions on a single chip. Are there chi... |
H: Powering 66 LEDs
I am trying to figure out some electrical values for a circuit I am designing. I am wiring 66 RGB CA LEDs in parallel. Each color channel takes 20mA (2.2v for Red and 3.2v for Green and Blue). How do I figure out the total ammout of current I'll need to drive each channel?
LED Datasheet
AI: If y... |
H: Does the Epson RX8900 real time clock count the year "00" as a leap year?
The datasheets ambiguously say...
A leap year is set whenever the year value is a multiple of four (such as 04, 08, 12, 88, 92, or 96).
Is zero a multiple of four? This is more of a philosophical question than a specification. The shown se... |
H: How to design a high impedance buffer circuit?
How can I design a buffer circuit that takes an input of +/- 10V and scales it down to a 0V to 5V.
The idea is to design a circuit that is microcontroller compatible (can be read by an analog-in pin by a typical 5V microcontroller) with input signals from Eurorack modu... |
H: Question regarding slew-rate
I have a question regarding SR effect.
Let's say that we have some simple amplifier with op-amp with the following parameters:
\$G=+10 \ V/V, \ f_c=1MHz, \ SR =1V/\mu s, \ V_{supply}=\pm 15V\$
The source signal is a square wave:
\$V_{in}=5V, \ \overline{V_{in}}=0V, \ f=10kHz\$
And I w... |
H: What is the best approach when writing functions for embedded software in order to get better performance?
I have seen some of the libraries for microcontrollers and and their functions do one thing at a time. For example, something like this:
void setCLK()
{
// Code to set the clock
}
void setConfig()
{
/... |
H: Design an SMPS to provide 5V – Transformer
I'm trying to design an integrated IoT device that will replace standard light switches. Currently I'm using a Switching Power Supply from eBay: HLK-PM01, just to have an working prototype. Now I spend over a week searching for example schematics, IC and others to create m... |
H: SY8113 based Buck Converter Voltage Regulator design
I am working on an Electronics design which incorporates DC-DC buck converter voltage regulators. This is the first time I've been working with buck converters, so I have no experience and only limited knowledge on their operation. I've already found a design usi... |
H: Large current draw at each cycle
I am designing a power circuit based off an older circuit for a similar machine, and have had a few issues in LTSpice simulator, where massive currents are drawn for the capacitors charging.
The image above shows the capacitors spike at the frequency of the AC input, quickly chargin... |
H: Pull-up resistor circuit clarification
I'm new to electronics and I'm trying to understand pull-up resistors properly. I have a problem with the following schematic:
I've redrawn the schematic into my following schematic for better understanding:
In the redrawn schematic, R1 represents pull-up resistor.
If we con... |
H: How to achieve positional servo control with an Atmega328P?
I am trying to drive my SG90 servo using the timers on the Atmega329P using phase correct PWM. I have set up my motor well enough that it rotates, but I cannot get it to stop - the servo motor just continues rotating.
Here's my current code:
servo.c
#defin... |
H: Transfering configuration to IEDs using IEC 61850
Sorry if this is a dumb question, but since I don't have much experience with IEC 61850 compliant devices, I am having trouble creating the "big picture" of how the whole system is being configured in practice.
Specifically, I don't understand how the devices which ... |
H: Open-source layout routing tool
I am looking for an open-source circuit layout routing tool (with scripting option) for custom layout design. For example: I design a NAND schematic and convert it into layout and place components (NMOS and PMOS) by myself and then auto-route it.
If found Qrouter from OCD but it req... |
H: Why is this the maximum dynamic range in a spectrum analyzer?
In Keysight's popular AN 150 there is a plot of noise and harmonics amplitudes versus the level of the input signal at the mixer (page 57).
It's stated there that the maximum n-th dynamic range is given at the intersection of the noise and n-th harmonic ... |
H: Use transitor as a switch to ground audio input
I have got a probably very dumb question. I was not able to find an answer on the other topics because they always described the use of transistor as a switch for other applications.
I have a circuit with audio signal passing through and going to a speaker. I would l... |
H: op amp current source oscillating
I know this topic has been discussed a lot, but there seems to be varying opinions about the solutions..
The problem is we are trying to make a current source with an op-amp driving a FET as the load. Our goal is to have a fairly high bandwidth for the regulating loop(couple of 100... |
H: Does this appliance break UK safety laws?
Good evening.
I recently purchased this active suction SMD pick-up tool from AliExpress:
When it arrived, it seemed to work fine. However, when I opened it up (to investigate the feasibility of adding a switch), I was less than impressed with the build quality and safety o... |
H: using sine or square wave to obtain conductivity of solution?
I see for designing a conductivity meter, Some Designer use square waves, as excitation to obtain conductivity and some others use sine waves for this work in their design, which wave do this job better for me?
AI: I am in the process of designing an EC ... |
H: Gyrator Derivation
I am trying to understand the input impedance calculation of this Gyrator circuit from Wikipedia.
The input impedance Zin is given as:
I am having trouble deriving this. My first reaction was to say Zin = Vin/Iin and setup a system of 4 equations to solve this. The math is not giving me an ele... |
H: How to set PWM frequency with high granuality
I want to create a PWM at 100kHz that can have 1000 steps. e.g. when I set CCR1 to 0%, the PWM is off an when I set CCR1 to 499 it should be 50% and obviously at CCR1 = 999, it should be full duty cycle of 100%.
The CPU_CLK is 80MHz...but I can not achieve this. here is... |
H: How does tuning in a spectrum analyzer actually work?
I have a pretty basic doubt about how tuning works in spectrum analyzers. I'm reading about the topic from Keysight's AN 150.
The problem arises in this paragraph in page 11:
We need to pick an LO frequency and an
IF that will create an analyzer with the
... |
H: S - parameters or scattering matrix
i have written in dsp.stackexchange.com, but guzs have written me this question would be better off on this site.
I have questions according to how to measure s- parameter.
I have a two-port network:
Normalized incident voltage
Now I would like to derive from measurements by s... |
H: Fitting USB Data in Cat5 Cable with External Power
I have a camera system at home with a DVR, which connects to a VGA monitor and mouse with which you can read and edit its settings (the cameras can be accessed over the Internet). I've been trying to move the monitor out of the closet it was in before (that's where... |
H: how do electrical arcs occur?
I was under the impression that arcs form due to high voltage, that the breakdown of air was typically 3 million volts per meter. However, arc furnaces typically use low voltages, around 30 to 40 volts, and high amperages, usually a couple hundred amps. Do arcs form from high amperages... |
H: Battery labeling
I hope EE.SE is correct, otherwise, please point me to the right SE
According to IEC 61960 chapter 5 cells must be labeled like:
A1A2A3N2/N3/N4
e.g.
ICR19/66
Yet, this information is hardly found on any cell in the market. Every big company only provides 18650 with some additional information.
Why... |
H: What is the name of this kind of connector where you stick a whole board in to connect?
An example of the connector type I'm looking for a name for can be found on this board:
It's the big box. You stick a board in to it with strips of exposed copper to connect. It also seems similar to how video game carts and US... |
H: Hard and Soft Chopping
I am controlling my BLDC (Brushless DC motor) controller with PWM technique by changing the duty cycle to reduce the power(current) in phase winding.
what is hard and soft chopping in PWM based controller(BLDC controller). Soft chopping is good PWM control technique compare to the hard one. ... |
H: How to calculate secondary RMS current of each winding in multiplre output flyback converter?
As I am designing multiple output flyback converter and I have confusion in selection of wire gauge of the secondary winding. There are 4 secondary windings and one bias winding. Mode of operation is CCM.
V_out1 48 V
I_... |
H: How do you know that an oscilloscope is displaying the actual waveform?
As oscilloscopes get faster and faster, when designing a new scope how do you know that what it's displaying is the same as the actual waveform? For the fastest scopes, you don't have something faster that you can use to verify that the measur... |
H: Can a 555 output be made to pull to ground?
I have design in Multisim with a 555 timer that I want to pull to ground when the signal changes. It's a missing pulse detector for resetting an mcu.
Is there anyway I can achieve this with say a transistor or mosfet?
I need it to pull to ground so i can reset a MCU.
AI... |
H: How to prevent polling using RS485
I was advised to use RS485 since I have about 7 devices needing to talk to each other (and cannot get CAN to work).
Although I want to start simple (two devices where one sends and other receives), later there might be multiple senders. One of the can be seen as Master, but others... |
H: S-Parameters math confusion
S11 for marker 1 says -47.661 dB
Two Questions
1st ..... What is | S11 | ^ 2
2nd
Is this accurate ?
g = 20 log_10(-47.661) dB
AI: 1st ..... What is | S11 | ^ 2
\$\left|S_{11}\right|^2\$ is a power ratio. -47 dB means a power ratio of roughly 2/100,000 or 0.00002 (because -50 dB wo... |
H: Matrix board without solder pads
I am sure there is an obvious answer to this question, so I apologise in advance.
I ordered some matrix board, but what arrived has no solder pads. Every matrix board I have used has the solder pads, and so I am not sure what to do. The board has the holes, just no pads... Is this b... |
H: Field Oriented Control Feed Forward Term
I implemented a Field Oriented Control (FOC) controller for a synchronous motor, which works already pretty good. Now the I-part of the PI controllers is necessary to achieve a good reference tracking, but slows down the dynamics drastically. I heard that a feed-forward term... |
H: NPN transistor as variable resistor for cc LED operation
I want to build a simple circuit, to control a chain of LEDs via an external PWM signal but limit their current. Unfortunatly I'm not aware of all the effects that the transistor would introduce to this circuit. If someone could point out any simple enhanceme... |
H: How can I power a device that requires 5-7V and 2.5-6 mA with what I have?
I have voltage pins on one device that outputs 6.23V DC and 70 mA DC. What type of circuit do I have to build that can power up another device that requires 5-7V DC and 2.5-6 mA DC using my 6.23 V source?
EDIT
The source outputs about 60-80 ... |
H: What information does one need to size inrush current limiting resistors?
I am trying to find a replacement for resistor Vishay CP00021R000JE14, a 1 Ω, 2 W ceramic wirewound (R_MED in the diagram). On startup, this resistor limits the current dumping into 200 µF of capacitance.
The instantaneous power is far beyond... |
H: Why do I see 0v on electret microphones?
I've got a few electret microphones and I tried to make this circuit:
It didn't amplify my sound, it continuously buzzed. Without mic it did same thing. So I probed mic and I saw 0.000v. Also 0mA (shorted).
I tested 5 microphones sitting next to each other, they all had sam... |
H: How do I make a circuit for a push switch that in order to turn on you need to press it 2 times?
Is there any way to make a switch circuit that turn a led on by pressig it two times thank you...
AI: The logic same but with improved simulation and faster switch debounce time.
Only glitch is it may need power up rese... |
H: Eleminating radiation from chargers
When I move my EMF radiation meter near a charger it shows me that there is radiation from the charger, and even the device itself radiates when the charger is connected to it.
The chargers emit radiation even if the device is not connected to them.
I understood that the radiatio... |
H: Output impedance of CNY70 circuit
I have a CNY70 sensor connected this way:
I read the output (the CNY1 port) with a PIC18F2550's ADC and in the datasheet, it tells me
The maximum recommended impedance for analog sources is 2.5 kΩ.
I want to know my circuit's output impedance because using common sense I can ass... |
H: Why do some IDC connectors have gaps?
At my work we use IDC headers and cable terminators a fair bit, and we've noticed that most headers have a gap on the sides (see image below). It looks like a clip would grab the gap nicely, but have never seen any cable terminators with any such thing. My question is why might... |
H: How to make an Arc welder out of 3500v bug zapper transformer?
I got a transformer from old bug zapper it has 3500v output , can I use it to make an Arc welder by removing the secondary windings and put 10 gauge wire windings instead.
I saw some videos on youtube to make it using microwave transformer, can I use t... |
H: Inserting an unused voltage source in LTspice messes up transient results
This took me three days to figure out. Consider this simple circuit in LTspice:
Looks pretty innocent. The output is a 1V sine wave, as expected. Going to View->FFT, setting number of data points to 5000, Start Time 50u, End Time 100us. No f... |
H: Help in the closing of a logic circuit
I'm currently studying logic circuits for my exams and came across a question "7. An electrical circuit is set up with four switches. A lamp will light only if the following happens:
Switches A and B are both on.
Either Switch C or Switch D is on, but not both.
Draw a logi... |
H: In a Wilson mirror, does Q3 need to have the same beta to cancel the base current error?
I'm learning about Wilson mirrors in the Art of Electronics Third Edition (pg. 102). It shows the following circuit:
simulate this circuit – Schematic created using CircuitLab
It then explains the circuit. As part of the expl... |
H: SPI fundamental question
I am a little confused regarding the order of bytes that are transferred through SPI to a slave device.
The next time diagram depicts the sequence of bytes to be sent when we want to write data to a a flash memory chip
After I send the command byte (first 8 byte to the slave device (Flash ... |
H: How is this piezoelectric effect converted to voltage?
The data-sheet of this accelerometer says:
This piezoelectric accelerometer may be treated as a charge source.
Its sensitivity is expressed in terms of charge per unit acceleration
(pC/ms–2, pC/g).
Is it possible to convert this pC/g to V/g? How is it con... |
H: Would I need a zero-crossing SSR for a reflow oven controller?
I'd like to follow this guide to create a reflow oven controller: https://apollo.open-resource.org/mission:resources:picoreflow
But I am confused on the zero-crossing SSR.
Does it need to be zero-crossing to control the heating element?
I already have a... |
H: ADC input range vs sensor output range
I am currently working on a project, where I need to calculate the current in a circuit. The setup is as follows:
Allegro ACS758 Hall effect current sensor (ACS758LCB-050B-PFF-T), primary sampled current -50 to 50 A, sensitivity 40 mV/A
Analog Devices LTC1968 true RMS-to-DC c... |
H: Setting Over voltage and Under voltage limits for LTC4364
I am trying to set under voltage, over voltage and over voltage clamping limits in a circuit for Overvoltage Output Regulator with Reverse Current Protection using LTC4364 device. The LTC4364 uses an external resistor voltage divider to set the over, under v... |
H: How to open up serial terminal for my USB device converter (or, how to enable VCP in linux)?
I am using a new Cyclone V SoC board by Enclustra (Mercury+ SA2) mounted on their PE-1 BaseBoard.
To connect to the board serially on Windows platform, I have to connect the board which is detected as USB Serial Device Conv... |
H: What command is sent from AVRDUDE to an AVR programmer for programming ATmega8
I have implemented an IoT ATMEL AVR Programmer based on protocol stk500, and I successfully connect with it wirelessly and program any ATMEL AVR Programmer through Arduino IDE, My Question is: I need for example the set of commands that ... |
H: Inductor for MOSFET protection
Help me understand the role and effect of an inductor used in the following electrical circuit.
The circuit in question is a power supply circuit for around 50 servers in a data center. The circuit uses a MOSFET transistor for commuting the power provided to the servers. In order to p... |
H: N-mosfet detects the proximity of my hand. Can it be useful?
When the gate of an N-channel MOSFET is not connected, it allows current to pass from drain to source, and the amount of current depends on the distance between my hand (or a piece of metal touching my hand) and the MOSFET (or a wire connected to the gate... |
H: what is the name of this yellow component in the motherboard?
I am not an electrician and I have no idea what is the name of this part on the image.
It makes a strange high frequency noise and I suspect thet the fault of this item causes my tv not to turn on. It has the following text written on its side:
MSC TY-T... |
H: Arduino logic level mosfet
I am currently trying to switch on a nichrome wire for about 5s using an Arduino and an external power source. It will be a single use only activation, I have decided to use an N-Channel mosfet for the job since space is limited.
The power source is a Li-ion battery and therefore I need t... |
H: Fixing an LED night light circuit
I bought an LED night light that's powered by three AAA batteries. At first it was super bright (too bright!) but then faded and finally went dead after just a week. It seemed to me that it didn't have an adequate current limiting resistor so I opened it up. It's simply 8 LEDs in s... |
H: Simulating all transient solutions for RLC series circuits
I am reading this page that contains the transient solutions for RLC series circuits: over-damped, critically damped and under-dumped.
This site presents these graphics for the 3 cases:
Then I have decided to create a simulation using multisim, at https:... |
H: Do you need a Pull down resistor when the line has an LED connected?
basically, since the LED is a diode that is tied to GND via a Resitor, does that mean it can double as Pull-down resitor for that line?
simulate this circuit – Schematic created using CircuitLab
AI: Generally a LED will not suffice, because when ... |
H: RF Attenuator Failure
I am attenuating an audio frequency (50 KHz) signal that is pulsed at 666 W for 300us with a period of 300ms. I estimated the power dissipated averaged over a period to be approximately:
\$\frac{300 \times 10^{-6}}{350 \times 10^{-3}}\times 666 = 0.5709 \approx 600\text{mW}\$
In the past, I ha... |
H: What does it mean to have dual input range?
Hi guys I am looking for a wide range input voltages DC-DC Converter as my inputs would vary from 12,24,36,42Vdc. I found this, the Murata NCS12 series which have an input ranges of 9-36V and 18-75V. Now what does that mean? Could it be I can input from 9-75V? Because it ... |
H: Is there a way to store matrices in an FPGA?
I just finished a Coursera course on hardware design (nand2tetris) and I want to take the next step and implement the design in an FPGA. Being fairly new to the hardware aspect of computing in general, I needed to clear a few questions regarding memory. In particular, I ... |
H: Guitar signal with opamp boost
Hi just having some issues understanding what's happening with my opamp circuit.
Vin is a Sine wave at 1kHz and VG is 4.5V.
From what I understand this circuit should boost the signal I provide it with my guitar. Simulated the circuit on LTSpice which provided the expected output at... |
H: About PIC programming
Hi friends iam new to PIC programming , I'm coding my pic in mikroC pro , please help me out.. iam attaching my file with this!the code i want is message from transceiver should receiver and check whether the message is ON or OFF then pic should function on my output accordingly!
AI: The compi... |
H: Press and hold the reset button to reset AVR!
I connected a tactile switch to the AVR reset button according to the circuit below. every time I press the button the AVR resets itself but my question is: Is there a way to make this button acts after let's say 3 seconds? I mean press the button and hold it for 3 seco... |
H: ESD protection on analog signals
I have a board which has its microcontroller pins directly breaking out to a breakout header.
I am fairly certain the board won't be in ESD safe environment when being tested.
I decided to get fairly standard ESD diodes and placed it across all Digital pins. They have capacitance i... |
H: Canceling ambient sound
I've just moved into a new flat and I noticed that there is a lot of car noise coming through windows. I know, I could just close the windows, but that's a less interesting approach to a problem. So last night, while trying to fall asleep, I started to wonder: Is there a device that could is... |
H: What is this silver component?
Anyone know what this silver component is? Tried to google it, but no luck.
Thanks
AI: That component is a surface mounted polyfuse. A resettable fuse that trips at elevated temperature and resets as it cools down.
These components are made in many package styles in addition to the o... |
H: Voltage Dividers for a beginner (with respect to soil moisture sensors)
I've just started with electronics and want to make an analogue soil moisture sensor (with Arduino).
When I looked online for an explanation of the working, every site said that it works as a voltage divider.
These are my questions:
What exact... |
H: What does NP and NO means in datasheets?
I will be using a DC-DC Converter from Cincon: EC4BW11
I do not understand what NP and NO means on the pinouts. I am assuming that the input voltage will be connected on pins 1 and 2 (+Input, -Input) and the output voltage on pins 3 and 5 (+Output, -Output) since this is and... |
H: Does wireless charging degrade battery life?
Does a design using wireless charging such as QI effect the longevity/health of lithium-ion batteries such as those found in modern consumer electronics devices?
What special considerations must be taken when incorporating wireless charging into a device to keep the batt... |
H: Decreasing and reading output of a sensor (0 - 10 V) using a voltage divider - Output impedance
I have a pressure sensor giving an output between 0 - 10 V.
I want to read and save the value using an arduino, so I am using a voltage divider (https://learn.sparkfun.com/tutorials/voltage-dividers) to scale it down to ... |
H: EAGLE schematic - capacitors and resistors all incorrectly connect to each other in BOARD
I'm relatively new to EAGLE and after watching tutorials I am trying to design a small board with (eventually) 16 low pass filters.
This is the schematic view, I am trying to make a low pass filter - ground, through capacitor,... |
H: Why do electrons move as if on conveyor belt in a circuit?
For example sometimes people will ask whether it matters what side of a component you place a resistor on. Surprisingly, it doesn't matter because electrons behave as if they're all connected together on a conveyor belt -- if they encounter resistance in on... |
H: Problem FIFO in the implementation (VHDL)
I was working in that for the past five days and I don't know what happened. I must implement a FIFO to send some information, I attach the FIFO that I use. As you can see in the code, this FIFO using three process update data, pointer process and send or receive data. The ... |
H: Why exactly a RLC Circuit powered by DC oscillates?
First sorry if the question is stupid... I am learning.
I am trying to visualize here, without equations, what happens to a RLC circuit that makes it oscillate.
Consider a RLC circuit, a switch and a 12V battery. Both L and C are initially discharged.
OK, I see th... |
H: Measured amperage differs greatly from my math
I've got the following circuit:
simulate this circuit – Schematic created using CircuitLab
It works. The LED glows nice and bright.
However my math doesn't match the readings I'm getting from my digital multimeter. Using Ohm's Law, I take the voltage rating of the bat... |
H: What is the definition of characteristic impedance of a lattice network?
We were being taught about Lattice networks in class, today, and our professor mentioned that the characteristic impedance of a symmetrical lattice network like
is given by:
$$Z_0=\sqrt{Z_aZ_b}$$
I'm not sure what characteristic impedance mea... |
H: Who said, "all sensors are temperature sensors, but some are better than others"?
One of my favorite electrical quotes goes something like "all sensors are temperature sensors, but some are better than others". Unfortunately, I don't remember where I read this. What is the origin of the quote?
AI: Whoever said it p... |
H: Power management problem on Samsung SI9000?
I have a Samsung SI9000 model SPH-D710 Sprint version. The issue I am having is the phone seems to not be charging the battery. Currently the battery is fully discharged and when plugged in and charging the phone charging icon on the screen appears and disappears quickly ... |
H: ceramic capacitance value
I am trying to figure out how to read the nominal value of this capacitor. When I use a meter it reads 3.4nF. I have several caps that have the format of .00X where X is an integer. Not sure how that decimal point works in there.
AI: Common capacitances range from 1nF to whole farads f... |
H: Toggle two LED status lights with two transistors
I have an input that is either floating, or grounded.
The switch is fixed, it's either open or closed. Ie, I can't replace with a double throw.
Here is the schematic / sim.
If the switch is closed, I want the lower LED to come on. If the switch is open, I want the u... |
H: can I replace a 2n2222 transistor with a tip31c
I have a TIP31c transistor, I need a 2N2222 for an Arduino project to drive small dc motors with PWM, I found both transistors are NPN, but I don't want to hurt my Arduino, is the swap possible?
AI: It should work if you get the pinning correct. The TIP31C is generall... |
H: Shift register Tri-State and ULN2803A
I was planning to use the SN74HC595 shift register in association with the ULN2803A and MIC2981 to switch on and off some loads based on the data of the shift register.
What happens if I disable the output of the shift register (using the OE line) and lines Qa to Qh go into hig... |
H: How to read maximum input
This is Carlo Gavazzi Power Analyzer, the sticker says
Input 3x380(660)V
Does it means that the maximum input voltage per line must be 380V or 660V?
AI: The "range code" of your product is "AV5", it means that your product can handle from 380V to 660V on its 3 inputs (-> tri-phase). The ... |
H: Node with two different voltages at the same time - Two branches (voltage source+resistor) in parallel - LTspice
I simulated the following circuit:
Why is Vu=7.5 V? I expect there to be an error because Vu=5=10 at the same time.
The current in the two branches is the same, thus (R1=R2):
$$Vu=R_1 i+V_1$$
$$Vu=R_1 i... |
H: Why is a microcontroller pin connected to ground via capacitors?
I am analyzing a circuit which uses an microcontroller to measure analog signals in digital form. I don't understand the function of one connection in the circuit.
See the figure. Here Vref of the MCU is connected to ground via two parallel capacitors... |
H: Use 0.5W speaker with PAM8302A cause speaker goes hot
I'm using PAM8302a (datasheet) and an 8ohm, 0.5w speaker. It seems the amplifier is too powerful for the speaker because the speaker's back turns hot after several seconds. PAM8302a uses 5V and the speaker is directly connected to VO_P & VO_N pins. How can I kee... |
H: Can I use an L7805CV with an AC input?
I am trying to switch a small water pump (for a pet fountain) according to the output of a PIR sensor. A couple of years ago I setup a circuit on a breadboard and tested it with the pump - it worked! Unfortunately, I don't have schematics or photos of the circuit anymore.
The ... |
H: Struggling to understand wire gauge and strands
I have been trying to understand wire gauge for a project, but there are so many different strand types and sizes it's alittle overwhelming. The wire needs to be 30 AWG and stranded, is it common for 30 AWG to have 7 strands or can it have more like 26?
AI: The strand... |
H: Can capacitors in speakers (Yamaha) be replaced by slightly different ones?
Now, I know that people used replacement capacitors which has a Capacity of 22nF, 250V ac and 630V dc +/-5%
The Capacitor was labeled C515 on the board it is soldered on.
I was wondering how flexible those values are. Does it have to be 22... |
H: Use battery supply as backup
I'm designing a circuit that has a built-in single-cell LiPo battery with its charger for a GSM circuit. The board feeds from a 12V power supply and uses the battery as a backup, and when the power supply goes out, the battery must power the load, and when the supply goes back battery s... |
H: How can the armature current of a DC shunt motor be zero at no-load?
I have seen the mathematical explanation of this explained using back EMF, where the back EMF would equal the input voltage and hence the armature current would be zero. But I'm unable to understand that if the armature current is zero at no-load ... |
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