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H: How much current is used with a μC GPIO input and pullup resistor?
I'm trying to understand power budgets a bit better and I have a question regarding pullups. I have a input to a microcontroller that needs to be logic high at all times. The micro goes to sleep now and again, so the internal pullup isn't an option.... |
H: gold finger plating needed on prototype board edge connector?
I am making a PCIe card and will be ordering prototypes.
I know that in my production cards I should order hard gold plating on the edge connector.
Can I skip this plating on my prototype cards to save expense and production time? I understand that the ... |
H: 2n2222a as a Switch
I just connected a very basic transistor as a switch circuit, and was trying to control it with a function generator with a schematic shown below.
simulate this circuit – Schematic created using CircuitLab
I set the function generator output to 1HZ , 5V peak(0-5v) PWM with 50% Duty cycle.
Howev... |
H: Extremely noisy signal after voltage follower/buffer
I am trying to create a voltage follower for my CCD linear array. When I measure the signal with oscilloscope directly from the CCD outptut - the signal is reasonably clean. However, when I measure if after the voltage follower, the signal is extremely noisy. Dis... |
H: how must I connect a USB micro b connector to reach 5v?
I'm designing a circuit and want to power it through a USB Micro B connector. I have already installed the connector on my board, but after connecting the USB female connector of the wire to my computer, I don´t get any voltage on the Micro USB B connector. Ho... |
H: How the time is converted into distance by multiplying it with 17,000
The general formula for Distance to Time conversion or vice versa is,
Velocity = Distance / Time
I have been implementing HCSR04 Distance Sensor,
Datasheet: https://docs.google.com/document/d/1Y-yZnNhMYy7rwhAgyL_pfa39RsB-x2qR4vP8saG73rE/edit
and... |
H: What is a SRF? (This is used in AC power distribution system with isolation transformer)
Following image shows a block diagram of a AC power system. What is that SRF equipment comes with the isolation transformer?
What SRF means and what it does?
AI: SRF = Self Resonant Frequency (as Dan D may or may not have sugge... |
H: Running current into a guitar pickup
When a guitar string oscillates over a magnetic-coil guitar pickup, the pickup produces an alternating current.
Would it be possible to do the reverse of this, and feed an alternating current into a pickup to manually oscillate the string? If so, would the signal type being fed ... |
H: Calculating current required for powering multiple robots in parallel
I'm looking to power multiple robots off a single 230V mains supply in parallel.
I'm using the Micro Magician V2. I can't find out how many amps it draws anywhere but I know the motors I'm using have a stall current of 760mA so I'd guess around 1... |
H: Making a bigger transfomer core by stacking multiple smaller cores
Does using a number of stacked EI or EE cores in the place of a bigger one (respecting the know magnetic characteristics) would pose any substantial difference?1
There's even manufactures that sell glued cores, but I think 4 stacked cores is the max... |
H: Simple calculator problem
So I am trying to create a calculator program in arduino using this codes.
void loop()
{
char keypressed = myKeypad.getKey();
if (keypressed != NO_KEY)
{
//Serial.print(keypressed - 48);
Serial.print(keypressed);
if(keypressed > 47 && keypressed < 58)
... |
H: Function setting on SPLC780D LCD
I'm drawing a bit of a blank with this. I have a 1602A-1 16x2 LCD screen hooked up to an i2c port expander chip.
I'm using the screen in 4 bit mode so I have DB4-7 hooked up to GPIO 0-3 respectively.
I have also hooked up RS, R/W and E to other GPIO pins.
I can see the function set... |
H: SPI Slave Flash programming with two masters question
I'm looking to make a system that can be upgraded by a customer in the field and I need to know some conceptual thing before I try implementing my current strategy.
Say I have a USB to SPI bridge, some FTDI chip, and I want to be able to program an SPI flash usi... |
H: Logical to physical implementation of voltage regualtor decoupling capacitors
For this typical LM7805 application :
simulate this circuit – Schematic created using CircuitLab
Due to bad planing when placing my components on the PCB (perfboard) I ended in the following phisical implementation :
So basically, on t... |
H: How can a circuit be unexpectedly affected by change in light levels?
I have (or rather, had) a completely functioning circuit the monitored input from a button to toggle an integrated LED on and off.
Much to my surprise, the circuit has very suddenly become finicky with light levels.
I have a lamp where I work and... |
H: Looking for replacement LED
I'm looking for someone who can tell me what kind of LED this is
(The barcode is: 5541475)
It's the blue LED from this projector: Acer K135
I'm trying to modify the beamer and replace the LED with a white one. Therefor I need a replacement which has the same structural shape. Would be a... |
H: How to make AC signal's level proper for MCU input?
I'm working on a frequency counter coursework, where I use MSP430 MCU. I have to measure
signals with specifications: frequency from 0.1 Hz to 1 MHz and signal's amplitude from 0.1V to 10V. The problem is with signal’s amplitude, I understand that the voltage of 1... |
H: Use CT current sensor to measure AC current of a single device
So I recently bought 3 current transformers with the goal to measure the current of 3 washing machines. All I want to measure is if the machines are running or not so accuracy isn't really a concern.
Now I ordered them a bit hasty and didn't think of th... |
H: How do I smooth current dips on a USB charger?
I've got a USB charger that I want to use to charge a phone. For about 35 seconds it outputs enough current for the phone to detect it and start charging, then for an instant (no equipment to read the length of time, let's call it a quarter second) the current drops t... |
H: Why are vacuum tube filaments internal
So, I'm a little fuzzy on vacuum tube designs, but I am under the impression that some use the filament directly as the cathode, while some use the filament to heat a plate which is the cathode. Since the filament is what burns out on a vacuum tube (I am aware of sputtering, b... |
H: Breadboarding a Raspberry Pi
Ok, long time reader first time asker on this parcticulair stack-exchange.
I am rather new to electronics, I've done some simple projects like Blinking Lights, alarms that go on when its dark and a Joystick Gamepad (with Arduino).
However, I am experianced in system programming, I've w... |
H: Active high and active low in IC
I am using an alu SN74ls181 . I am unable to figure out how active high and active low are decided . Is it during the manufacturing or some circuit parameters decide if the circuit is active high or low.
AI: The chip does not care, it reacts to voltage levels, not to logic signals.... |
H: What might cause audible noise in an inductive charging system?
I have a pair of Qi-compatible wireless charging pads, and I've noticed that when a device is charging, the pad will emit a quiet but noticeable squeal in a relatively high frequency range. Perhaps it's because the pads sit on my desk near my bed, that... |
H: How to do a DIY LCD output from a busted android tablet?
I have a cheap android tablet with a busted screen. Replacement screens cost more than a new tablet and I hate to waste it since it's only a few weeks old. I took it apart and it runs on a Allwinner A13 ARM chip. The LCD section of the data sheet doesn't s... |
H: noise caused by square wave signal
I am using electronic switches to create non-TTL square wave clocking. The oscilloscope graph demonstrates two measurements:
Yellow signal: 0-8V
Blue signal: 0-5V
As you can see, yellow signal is contaminated with small voltage jerks every time the blue signal goes high or low.
I... |
H: "two bypass/decoupling capacitors" rule?
I found many discussions on bypass capacitors and their purpose. Usually, they come as a pair of 0.1uF and 10uF. Why does it have to be a pair? Does anyone have a good reference to a paper or an article, or could provide a good explanation? I wish to get a little theory on w... |
H: What is the schematic capture/PCB layout design cycle?
Is there somewhere a description or flow-chart of the process of designing a circuit: Requirements analysis, schematic capture, simulation, PCB layout, etc. as well as various checks? Something especially for PCB design, and not so much about IC layout please.
... |
H: Minimum voltage for DC amplifier
Based on Detecting a low pulse from an electromagnet induction,
I was planning to amplify a DC sine/sqaure wave, however the peak is less than 50mV.
What is the smallest voltage peak that can be amplified using a DC amplifier?
AI: There is no real limit to amplifying even a sub pico... |
H: Making passive speakers louder
Just bought some passive waterproof speakers to be ceiling mounted in the bathroom. They're 80 watt, 8ohm, pretty bog standard. The problem is this - when we have e.g. an iPod plugged into a cheap Bluetooth speaker via a 3.5mm audio cable, it produces an acceptable volume. However, wh... |
H: How to gauge resistance on parallel circuit with step down buck regulator
I'm trying to create a circuit with two loads in parallel ( essentially piggy backing one circuit on the power supply of the other ). Circuit 1, the main circuit requires ~900ma at 12v. Circuit 2, requires ~70ma at 5v. To step down I'm using ... |
H: Is there a difference between TI brand of the 74HC595 and the NXP brand?
I have been trying to figure out the functional differences between TI's version of 74HC595 and NXP's version. I've been looking at the function tables in the datasheet for TI and the datasheet for NXP but am having a hard time determining if ... |
H: Is there a standard reference designator to use for labelling indicator lamps in schematics?
In a schematic, LEDs typically are labelled using the letter 'D' since they are diodes. From what I can tell, it seems that there is no standard for labelling indicator lamps (e.g. small incandescent bulbs) in a schematic.... |
H: What do peak-to-valley and mm/µV mean?
I was reading a document where it says
Adjust the signal generator to apply a 1mV peak-to-valley input 6Hz
triangular signal at a gain of 0.001mm/µV.
What does peak-to-valley mean hear? Is it same as peak to peak?
And, what does mm/µV mean?
AI: Peak to valley means the h... |
H: Auto-ranging voltmeter circuit with PIC uC ADC
I want to design an autoranging voltmeter with a PIC microcontroller and its ADC.
Requirements:
Measure voltages from +0.2v to +50v
Protect against reverse inputs or slightly higher voltages
Input impedance can be quite low, drawing up to a few mA.
Accuracy of arou... |
H: GPS USB device with external coax antenna?
I've been looking around for a bit searching for a USB connected GPS reciever which i can hook up to my laptop. However, the building i'm sitting at is not ideal for recieving GPS signals but i do however have a antenna tower ontop of the building which i could mount a GPS... |
H: Which electronic parts/systems are responsible when installing an OS to an empty PC?
I´m wondering there must be some already commands inside a computer to be able to install OS such as Windows. Somewhere there must be a programmed chip or something. Is that DOS? Any introduction link about this appreciated.
AI: Th... |
H: Identify which face of a cube is up
I have a device whose shape is a cube and I need to identify in real time which face is up.
My current solution is (not yet implemented) is to use a gyro to get angular variation, but I can see 2 problems:
Which face is up when the cube is "powered up"?
We can't assume that ever... |
H: How do I size fuses to handle sudden changes in AC line voltage into a capacitive load?
Suppose I have a rectifier on the AC line, followed by some caps and a load.
simulate this circuit – Schematic created using CircuitLab
If the AC line is suddenly increased, there's a current surge into the capacitor. This can ... |
H: What is the difference between a transformer and a coupled inductor?
Transformers and coupled inductors seem very similar. Is there a difference in construction? Or only in use?
This question asks something similar, but the answers don't address my question:
Coupled inductor vs an actual transformer?
AI: The two ar... |
H: Powering high power LED modules/plates (series parallel internally)?
I am trying to build a high power RGB LED light. I am looking for 50W-100W range for the LED (all colors combined). 100W RGB LED desn't seem to exist so I am left with 50W, 60W, or 90W options. I would prefer higher wattage single LED module as it... |
H: What is the percent impedance of a typical residential power line transformer?
Power transformers are rated by percent impedance. A 5% transformer, when loaded to full spec secondary current, will show a ~5% deviation from nominal output voltage.
What is the percent impedance of a typical residential power transfor... |
H: MOSFET specification help
I am designing a system that uses a large amount of power. The MOSFET will be to turn off the batteries when mains is in use. The FET will therefore be on or off. No pulsing.
The voltage will be between 34.5V and 20V with about 30A max of current draw.
Can someone please explain what ... |
H: PCB - single battery design
I've designed an analogue front end for EMG signals that I want to turn into a PCB. However currently it runs off of two 9V batteries which makes the end product quite large and heavy. I was wondering how I would go about changing my design (or components) to a single battery supply?
Tha... |
H: What is more accurate definition of Ohm's law?
What is more accurate definition of Ohm's law and resistance?
is it
$$R=\frac {V}{I}$$
or
$$R=\frac{dV}{dI}$$
This is doubt that developed in my mind during a class where professor derived power equation where he used second one for resistance in the derivation. I chec... |
H: Multiplexing and electric capacitance
I'm working on a project, it's basically a hand-drawn paper keyboard based on capacitance.
I was thinking I can multiplex the different lines with shift register (74HC595) and switch (4066), and as I've got a lot of these here I gave them a try. But apparently not...
So I'm loo... |
H: What are the construction differences between a 1% transformer and a 5% transformer?
I'm told that a 1% transformer costs more than a 5% transformer of the same power rating. I understand that the 5% transformer has higher output impedance, which seems to imply more windings and thinner wire. Is this the only const... |
H: Apparent power in exponential form
On page 2 of this PDF, a voltage source \$V= |V| e^{0}\$ is connected to a load \$Z = |Z| e^{j\psi}\$. Then, the apparent power is described as
$$
P + jQ = \frac{ |V|^2 }{2|Z|} e^{j\psi}
$$
However, I think the power should be
$$
P + jQ = \frac{|V|^2}{|Z|} e^{-j\psi}
$$
Where di... |
H: Why does the voltage of a zener diode match the voltage at Vout?
In this circuit, if:
Vin = 9V
Vz = 5V
I understand that Vout will be 5V. Does that have to do with Kirchhoff's Voltage Law? How does the zener diode, if it drops 5V to ground, cause Vout to also be 5V?
AI: Zener diode passes a lot of current (has l... |
H: Why don't hall effect current sensors exist for low currents?
There do not seem to be hall effect current senors available for small currents, say on the order of 500mA. I'm guessing this is due to some technical or physical limitation. What is it?
AI: Hall effect current sensors measure the magnetic flux generated... |
H: adafruit rf m4 as a ground switcher
I have a store-bought battery powered LED light assembly that is controlled by a microswitch. The light is installed in a hard to reach place so I wanted to hook it up to a cheap ASK wireless receiver with a remote. I bought the RF M4 (http://www.adafruit.com/products/1096) fro... |
H: synchronous buck ls-FET switching losses and dead time minimization
I'm designing a Synchronous buck converter. I'm having doubts regarding the following:
In the rectifying period of the converter, using a Schottky diode in parallel with the low side MOSFET will prevent the body diode from conducting, and so it sh... |
H: Shift register m74hc165 connection
I am following the following tutorial (http://www.arduino.cc/en/Tutorial/ShiftIn) to connect a shift-in register to my Arduino. In the tutorial they use a CD4021 'CD4021' shift register and I got a 'm74hc165'. After looking at the datasheet (http://www.datasheetlib.com/datasheet/7... |
H: How can a capacitor store charge whilst also passing current?
It's frequently said that capacitors store charge. Just reading through Wikipedia, I find:
Daniel Gralath was the first to combine several jars in parallel into a "battery" to increase the charge storage capacity. Benjamin Franklin investigated the Leyd... |
H: How to program Arduino Nano / Pro-Mini / Pro-Micro clone that has no usb port?
I was looking for a cheapest possible option to get arduino and wireless comms for a dimmable light and come across this ebay item when searching for Arduino Nano clone. It has no usb port so how can it be programmed?
Edit:
I have discov... |
H: AVR ISP - SCK pin shared with LED
I made a board with an AVR Attiny MCU and an ISP connection. I missed that I made the SCK pin an output for an LED. Luckily, this arrangement seems to work; I can program the chip just fine. But, during programming the SCK signal from the programmer is driving the LED on. Is this o... |
H: Any tricks to attaching a wire or pin to a testpoint?
More and more often, I find myself needing to tear apart a device to seek out and connect to serial pads. These pads typically give me access to the underlying operating system for research or tinkering, of which I'm perfectly comfortable with.
What I'm not comf... |
H: How do i get a transistor to work efficiently?
I'm trying to improve my noobie SMPS design (230v AC -> 60v DC) and i have a major issue with the efficiency. Currently the sim says it outputs 425W while eating 2.2kW, and most of the difference is lost in the main power mosfet.
I think the problem is that the mosfet... |
H: The cheapest and smallest way of converting 3 V to 3.3 V
My microcontroller operates at 3.3 V, but all the CR2032 bateries are rated at 3 V. Is it safe to drive my microcontroller using this 3 V? Will it operate correctly?
I don't have to draw too much current, so the current is not an issue. If not, do I have to ... |
H: SDRAM initialization
I've been trying to study how the ARM bootloader works, but initialization of SDRAM is still somewhat a mystery to me. For example AT91 Bootstrap uses following function for initialization. I think I understand most of the steps, but why step #7 (8 auto-refresh cycles) is needed?
int sdramc_ini... |
H: position locator using zigbee
I am working on a project to count the number of cars in a specified region. I would like to use a Zibee/Xbee module. As far as I've learned, Xbee modules are used as stationary nodes and Zigbee modules are arranged in the car. There is a gateway node that receives the data in terms of... |
H: Can you use arduino for other avr chips?
Example:
Arduino leonardo uses Atmega32U4. What if one wants to program/develop for the plain ATmega32.
AI: You can use the Arduino IDE with any MCU you can find compatibility files for. You may need to use a ISP programmer though, unless you can also find an appropriate boo... |
H: How to edit dimensions for PCB layout in proteus
I need a relay like this in proteus
http://www.sanyourelay.ca/public/products/pdf/DI1U-K.pdf
the DI1U-P type.
unfortunately all the relay i found are not of the same size.
please help me on how to change measurements in the package.
AI: This can probably be explained... |
H: Problem with Atmega 168 USART receive interrupt ,while communicating with Xbee
Before decreasing my reputation please let me know what I have done wrong. Bear with me as I am a newbie.
I have written a program so that a receiver radio module sends 1 when it receives an 1 from a broadcaster module.I am using XCTU wi... |
H: Reducing system voltage whilst getting the same output from a PCB antenna
I have built a small prototype transmitter, based on a schematic available online. It transmits on a 5Mhz carrier and uses BPSK modulation. It works well enough for my purposes.
The schematic for the TX output section looks like the below:
... |
H: PIC XC8 compiler array of structs?
I'm having trouble assigning variables to structs, particularly making an array of structs, with the XC8 compiler.
Example code below:
typedef struct p{
int id;
dateStamp start;
dateStamp stop;
int parent_id;
} period;
period p1 = {1, {0, 0, 0, 1, 1, 14}, {20, 0, 0, 1, 1,... |
H: DC Motor Control - h-bridge pulsing strategy?
Question is with regards to a DC motor controller built around an Allegro A4940 and four discrete FETs.
There are at least four possible strategies for driving the FETs, and I'm struggling to understand if any one of them is the accepted "right" way or if the best choic... |
H: A program to add 6 bytes of data and store sum and carry in 8085 instruction set
I have a question on 8085 instruction set.
A program to add 6 bytes of data stored in memory starting from 4500h. must use b register to save any carries and finally store the sum and carry at two consecutive memory locations 3000h and... |
H: ATX Computer PSU: OK to connect loads between positive rails, e.g. +12v to +5v
I have looked, but haven't find an answer.
Are ATX computer PSUs capable of having a load connected between their positive rails, so that for example, current would flow from a 12v rail to a 5v rail?
Specifically, I need to know:
Does t... |
H: Solve this Linear Circuit
Consider these relations about that circuit bellow:
$$i_2 = i_L\\
V_2 = V_L\\
Z_2 = Z_L$$
As reference the circuits below on pictures I and II, is correct to affirm that the value of Voltage $V_x$ can be calculated by this equation:
$$\frac{V_x-V_0}{R_0} - I_0 + \frac{V_x}{R_1} = 0$$
Answe... |
H: What can I do to decrease the latency from these serial ports which are attached to a PC via a Serial to USB adapter?
I think I have accidentally discovered a need in my life for embedded systems. Which is great! And kind of scary. And I need help.
Background: I got hired to build a GUI application which takes scan... |
H: What does ".1M/250" mean as a capacitor rating?
I'm not very familiar with capacitor markings, and I'm trying to understand what exactly this one means. I'm guessing .1M indicates 0.1 microfarads with 20% tolerance, but I have no idea what the /250 means.
I don't have any documentation for it since I just pulled it... |
H: How would I make an Arduino Due recieve RS-232/422 signals?
Background on this question is here: What can I do to decrease the latency from these serial ports which are attached to a PC via a Serial to USB adapter?
I'm looking at purchasing an Arduino Due to take in 3 (well, ultimately 5, but currently 3) serial si... |
H: Battery Elimination Circuit Powering Flight Controller
I am putting together a quadcopter, and one of the things I've stumbled across that I don't quite understand is Battery Elimination Circuits (BECs).
The Flight Controller on my quadcopter is a modded Arduino board with some motor pins and other sensors integrat... |
H: Op amp non-inverting circuit mystery
I'm working on a project with lots of op amps and so far had no problem but this one is driving me nuts. I need a 1:2 non-inverting amplifier which I built on breadboard but doesn't work as expected. The circuit is trivial, I tried different op amps (LM741,TL072,LM358), use a ra... |
H: DMA completion interrupt not working for slave STM32 SPI
I am using stm32f103 to transmit some data over SPI while stm32 acts as slave. I need to use DMA for sending data to the SPI but the corresponding interrupt handler is never called.
The initialization code comes in the following:
DMA_InitTypeDef DMA_InitStruc... |
H: How to find a problem on a Non working Yamaha SPX90 (Pro audio) effects unit
I have an electronic processor unit namely an SPX90 (a 19" pro audio effects unit made circa 1987). I'm a home studio producer and have owned it from new from 1987, but it died a few years ago. Now thanks to this SE, I'd like to find out h... |
H: How to wire/interface a 4x3 membrane keypad
I followed this example to wire my keypad to my STM32F4 Discovery board. However any way I read data on the pins I keep getting same data which leads me to believe I wired something wrong.
Here is the image how I had it wired:
I the red line (+) on the breadboard is wire... |
H: Can I run this motor off of this solar panel?
I am trying to build a solar powered boat, and I have decided upon this 5V, 500mA panel. I can buy 3 or 4 of them to get up to the necessary voltage and amperage. The problem I have is that I can't find any good 5V motors; the closest are 6V, however as far as I know yo... |
H: Logic gates q's on unconnected and mid-range inputs and gate output
Why do TTL integrated circuits assume unconnected inputs to be at logic 1?
What is fan-in and why is it important in the operation of a logic gate?
What happens to the gate output of NOT logic gate when its input voltage level reaches from 0.4 V t... |
H: how to draw a timing diagram for a logic circuit
Hello does anybody have a guide to drawing timelines for logic circuits? For flip flops like this
Basically I want to draw corresponding timeline for any circuit like this:
AI: Generally, you want to show the external inputs at the top (like your diagram does), and ... |
H: Why is the voltage output from an arduino positive?
If I connect the common ground (COM) probe of my voltmeter to the positive side of a 9V battery and connect the voltage probe to the negative side, I read -9V (or thereabouts). This lines up well with my mental model of non-conventional current flow and how it's t... |
H: Increase Amperage With Capacitors without any change in voltage
I want to know how to increase the current/amperage without changing the amount of
voltage. I found this formula:
I (t) =
Vs/R * e^-t/RC
from this website:http://www.ehow.com/how_8780713_increase-amperage-capacitors-diodes.html
but i don't unsersta... |
H: Simulation of inverting summing amplifier not working and finding it's parameters
I have a project to create circuit of inverting summing amplifier with 3 inputs and a simulation on it. I am using capture (OrCAD Pspice) and so far I got to the circuit you see below, at the end of this wall of text. The circuit is s... |
H: Calculating Impedance for capacitor in AC circuit with some undefined waveform
I need to set up equations for some simple AC circuit. The problem is that I dont know the formula, definition for the resistance.
I know for the 1/2*PI()*f*C, but I think this is only valid for the sin, cos, waveforms.
My question: is ... |
H: What are the consequences of oversizing resistors?
When building a circuit to power an LED, we use Ohms law to calculate the required resistance, then to calculate the required wattage of the resistor. Suppose this formula dictates a 1/8 W resistor, and I instead use a 1W or a 100W resistor of the correct resistan... |
H: Step up DC-DC converter for powering Raspberry Pi from batteries
I will power a Raspberry PI with 4 NIMH batteries, but they quickly lose charge, and end up at 3V instead of the 5V needed. I was wondering about a DC-DC step up converter.
I want a converter that will have a fixed output and will not be affected by ... |
H: Are some implementations of SPICE more accurate than others?
Just like the title says. Is there one single SPICE back-end that's the same for different versions of SPICE, or are the different versions performing different simulations?
AI: The general approach to SPICE simulation is more or less the same for differe... |
H: Changing iron's pilot lamp connection, will it still work?
I have restored a Rowenta E5291 heavy clothing iron, a remake of a vintage model, and I changed the pilot lamp's connection.
I made this change because this iron can never be turned off unless you unplug it so I modified the bimetal switch to allow it to be... |
H: AC solenoid valve with DC
I have a 24VAC/60Hz solenoid. I used 12VDC just to try, and it worked good (well needless to say it worked as expected with 24VAC/60Hz).
What are the effects of a solenoid that's designed for AC running with DC? Applied force does not seem to be a problem in this case, so I think the main ... |
H: PIC18 microseconds counter
I want to count microseconds between timer's ON/OFF. My FOSC is 48 MHz.
I figured out timer1 would need to be initialized like (I'm programming in mplab):
// Freq = 1000000.00 Hz - Period = 0.000001 seconds
T1CONbits.T1CKPS1 = 0; // Prescaler rate
T1CONbits.T1CKPS0 = 0; // 1:1
T1CONb... |
H: Should I define default register values in start up code?
It has come to my attention that some ARM programmers set some CPU registers with values that are the same default values of the register on microcontroller reset.
For example: the default value of IOCON_PIO2_9, parameter MODE on LCP1114 is 0x02 (pull-up res... |
H: What is "transformer connected" vs. "direct connected" for a electricity meter?
I am looking at sub electricity meters. Right now I am reading about the ABB product line EQ. In the documentation (link to PDF, "Electricity Meters - For modular enclosures and DIN rail"), they split the products into two categories, t... |
H: Are there rules for selecting wire gauge for single-pulse applications?
I'm trying to size wire for UL 508a panels. I have UL's wire gauge requirements, but those requirements are for continuous use. The device I'm designing will only run for two seconds, with minutes or hours between runs. Since currents of intere... |
H: Inverting OpAmp with reference voltage
Can anyone please explain how to calculate Vout for both cases below?
1 case, simulation shows Vout is -1V
2 case, simulation shows Vout is +2V!
I understand how things work when there is a virtual ground, but when there is a reference voltage applied and resistor on the feedb... |
H: What is the maximum output current of an OP27?
How much current can an OP27 supply (happily) ?
The closest thing I can find on the datasheet is the short-circuit current (~30mA).
AI: I think this is as close as you can get to an answer
It basically shows you the max current vs output load, all it takes is a divisi... |
H: Capacitor with op-amp
if we connect a capacitor with charge = 5 volts , with buffer (op-amp) , will the capacitor will discharge it's voltage ? or because of high impedance will keep it's charge ?
simulate this circuit – Schematic created using CircuitLab
AI: In the ideal sense, that capacitor will hold its charge... |
H: op-amp and capacitor 2
if i have the following circuit , what the expected behaviour of the following caps ? , it will be charge and discharge very quickly since we have a low inpedance form op-amp?
simulate this circuit – Schematic created using CircuitLab
AI: I expect this will oscillate or otherwise not behave ... |
H: When do we use all pins in RS-232 cable?
I think the minimum for simplex communication are TX so we can transmit and the power supply pins +Vcc and GND. That is all we need. When do we need to use all 9 pins of RS-232? I think that the reciever can decipher when data has started coming in and if it knows the baud r... |
H: Low cost high precision linear position sensor
I am trying to find a low cost high accuracy linear position sensor that can be used in a hobby 3D printer. Almost all current 3D printer designs rely on stepper motors to provide positioning but I want something that works on positioning info rather than assuming the ... |
H: GPIO/PCIe programing
I want to connect a PCIe 16x 3.0 GPU card to a Raspberry pi. I don't mind lo loose bandwidth, i just want to use the core GPU capabilities. So, the only idea that came out to my mind is to use the 26 GPIO RPi pins. I am concern about the GPIO/PCIe programing, do not have any idea neither an app... |
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