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Questions tagged [power]

Where power is a primary concern for the design under discussion. Use the "low-power" tag when that applies.

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85 views

Safety Capacitor Selection

When selecting an X2 safety capacitor what must be taken into consideration. There are only a few types of capacitance ranges and seem to be chosen based on voltage rather than capacitance. Take ...
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92 views

Can this example be used for explaining the effect of lamination on power loss in a power transformer?

I'm trying to demonstrate to a group of people how a lamination of the transformer core reduces the power loss due to Eddy currents by not using any complex math. I start with a non-laminated core as ...
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164 views

What determines the actual power consumption of writing to a microSD card?

I'm currently working a project that will feature writing data to a microSD card. Because my project will be battery powered with a 125mA power regulator, I'm concerned that my write operations will ...
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2k views

How to make your own EL Wire (electroluminescent wire) inverter

I would like to make an EL wire (electroluminescent wire) inverter because I can't seem to find a commercial inverter that can drive the right length of wire from the batteries I would like to use: ...
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14 views

Context of Li-Ion MnO2 “Cell Configuration” Specification

My application supports variable pack configurations: 4S4P, 4S6P and 4S8P. Each one obviously uses a different BMS profile, and other minor changes such as charge/discharge MOSFET and fuse selections....
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39 views

Hamiltonian-inspired energy function for power grid stability

I'm looking at this paper which proposes an energy function for a 3-bus power system example. I'm trying to replicate the results in the paper but am uncertain about the ...
2
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0answers
95 views

Overshoot/undershoot issues in load current wave form of a MOSFET

We have designed hardware circuit which validates voltage regulator maximum output current. So we designed op-amp circuitry to control gate drive of the Power MOSFET and it will work in active region ...
2
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0answers
27 views

Way of powering Arduino+GSM Modem+Cam off 5V powerbank

I'm trying to build a circuit, that would turn the Arduino on by a PIR sensor, take the picture by ArduCam, then transfer it onto a webserver. I got the SW site covered by now, so that is not a big ...
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119 views

Why does my SEPIC converter output more power at higher temperatures? What are the implications of this behavior?

I have a Pololu S18V20ALV SEPIC voltage regulator board that is wired to a high-amperage 5V USB power source on the input and a DC brushless fan on the output. The output is set to about 5.5V. ...
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115 views

Q: What is the power of this signal

Determinate the power of the discrete signal: $$x[n] = u[n] + (-1)^n + (\frac{-1}3) ^n * u[n]$$ where: $$u[n] = \begin{cases} \ 1, & n \ge 0 \\[2ex] 0, & n \lt 0 \end{cases}$$ The answer ...
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80 views

Audio: Camera activated external microphone

I want to build a relay circuit that turns on an external microphone (powered by an internal 9V battery) when a connected camera is turned on (a camera offering only 1V plugin power through a 3.5 mm ...
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406 views

What's necessary to properly decouple/filter a PWM-controlled fan from an Arduino?

I've got a small problem I could use some help with. I am using an Arduino to control a cooling system I am building for a DSLR. Primary goals are to use PWM and some pots to control TEC power, as ...
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0answers
95 views

Getting more than 0.5W from USB OTG

Has anyone actually measured the maximum amount of power that can be drawn from a smartphone's (say Samsung S4) USB OTG in host mode? I've read people suggest 100mA but can't find if anyone has ...
2
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0answers
352 views

Strange stepper motor behavior- moves too far

I have 3 CD drive stepper motors on a 9V 2A power supply, and they are being driven with EasyDrivers. I am using an Arduino with grbl to control the drivers. The current for the motors is at the ...
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0answers
18 views

Split Power Plane when using Load Switches?

To do power saving for a battery operated product, I am using couple of load switches to shut down peripheral power when not using that. PCB stackup - Signal(component), Gnd, Power, Signal -- 4 ...
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0answers
37 views

Issue with powering MP3 module with Amplifier

I'm not a electronics engineer/student, so please escuse me if my query sounds a bit naieve. I have a Mp3+FM module (link) which I can power with a regular micro USB charger(or desktop USB). As the ...
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0answers
44 views

What factors should I consider when choosing a high amperage power supply?

I've searched around, but I haven't found an answer to this particular question yet. I'm building an elecromechanical project which requires somewhere around 60 Amps at 12 Volts. While this may not ...
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36 views

Designing a +10 V -10 V +7 V DC power supply for audio equipment

I've recently purchased a tape recorder (Tascam Midistudio 644) that was very cheap because the previous owner had lost the power supply. The PS-M1 power supply that originally came with this unit is ...
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0answers
31 views

Inrush current limiter circuit for filament bulb - comparison

Context: A 12V power supply is switching on externally connected 12V filament bulbs. The power supply's load switch implements an electronic resetable fuse (13A/τ=15ms) in case of an external short. ...
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0answers
27 views

MPU6050 hangs on ESP32 when operated using a battery on custom board

We are facing a very peculiar problem. We are designing a board based on ESP32 with various peripherals like motor drivers, sensors etc. We are using GPIO 4,5 on the ESP32 as I2C lines and have hooked ...
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0answers
18 views

Hook up an automatic transfer switch with two phases only

We have a house in Haiti connected to the shore line. The shore line isn't always working so we bought a generator. I wanted to ground one of the two phases to create one neutral, one phase and a ...
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92 views

Power consumption measurement on the bench

I've been using the Atmel Power Debugger to sort out power consumption issues on some µController based circuits... and have been pretty pleased. Unfortunately, it's limited to a maximum of 5.5 volts ...
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148 views

IGBT failure and protection

I have a 3-phase bridge rectifier (shown below). I am using an IGBT (STGE200NB60S) to limit the inrush current from the capacitors at start up. I also added the NTC thermisters to help with the inrush ...
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0answers
50 views

Is there a cost savings associated with 3 phase power at the same device power requirement (kW)?

I am a Mechanical Engineer looking into purchasing an annealing furnace and have seen that some operate on single phase power while some operate on 3 phase power. I've done some research and have seen ...
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0answers
42 views

Brick SMPS power supply issues

I'm working on a system comprised of two boards (power board, screen board) powered either via European outlet (220v 50Hz) or a LiPo battery. Power handover is achieved via an autoswitching MUX that ...
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141 views

Soldering sheet busbars to PCB concerns

Hello fellow engineers I have decided to solder busbars to a high current pcb , but i have 2 concerns : Does soldering a flat busbar (shown in left image) could cause thermal stress and deformation ...
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86 views

Are there commonly used equations for short-term overpower of wirewound resistors?

If I have a wirewound resistor rated for 250 W that might need to dissipate, say, 400 W for several seconds, is there a commonly used equation for finding its temperature rise or time to failure under ...
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0answers
71 views

ESP8266 shutting down while powering a mosfet only when said mosfet has a high current load

I am working on a small quadcopter based around the ESP8266-12F. I used a trace width calculator for all PCB traces as well as a 100uf tantalum capacitor shared by all motors to ensure low voltage ...
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0answers
55 views

Y/Y/Δ or Δ/Y/Δ transformer for a series connected 12-pulse rectifier?

I'm aware that 30° shift is needed in order to obtain a 12-pulse rectification, however, I'm a bit confused about the configuration of these transformer. In most HVDC systems that appear in Alstom - ...
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70 views

aluminum anodizing power supply schmetic

It has been a long time since I played with the electrons. In my day filament transformers were common and power supply design included the number and type of tubes being used.LOL Anyway I need to ...
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91 views

Gate Driver Not Working as Expected. Why?

I am using the ADuM5230 gate driver to drive an N-channel MOSFET in a basic buck converter circuit that will convert a 12V DC input to a 5V DC output. The buck converter will operate at a 10kHz ...
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22 views

Smallest signal level a ZBD (WR3.4ZBD from VDI Inc.) can detect

We have bought a zero-biased-detector(ZBD) working at 220GHz-330GHz. The specifications gives Typical NEP of \$17.6pW/\sqrt{Hz}\$, but there was no specification of what is the smallest power level it ...
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45 views

Daisy chaining power through mcu modules

I am really sorry if the following question is too obvious and basic, I am trying to understand how I can do this right. I have five 5V PIC custom modules that I am trying to power, using a daisy ...
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152 views

Which power factor is better in an industry -0.21 or -0.94 and why?

In the electrical panels , when i switched on-off the capacitor bank then power factor gets shifted from 0.89(lagging/during OFF condition) to -0.87(leading/during ON condition) , similarly on ...
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0answers
148 views

Magsafe to USB-C adapter

I would like to create an Magsafe 1 to USB C adapter to re-use my macbook magsafe charger on my usb-c macbook. I have these components below and already tried to connect both V+ and Ground with no ...
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61 views

Power sequencing with LDO without enable pin

What is the right way to provide a power sequence using LDO (or any other power source) without the enable pin? I'm using DAC7718 from Texas Instruments and it require a quit complex power sequencing:...
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0answers
52 views

Designing Battery Power System For Robotics

I'm building a mobile robotics project for a class and I'm trying to figure out how to (or even if its necessary) to design a nice battery power system for it. I sort of wanted to learn how to build a ...
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0answers
85 views

Am I right about measuring current, and power

I have a meter that can measure: current, active power, reactive power and complex power. simulate this circuit – Schematic created using CircuitLab So, when I measure the four things: current,...
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0answers
403 views

Potential difference between DC floating power supply and earth ground

I have a question about a simple DC floating power supply: it is as simple as possible, secondary coil -> bridge rectifier -> filter cap, as shown on the figure below. If I connect the input of the ...
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0answers
62 views

Is my millijoule (mJ) calculation correct?

My partner and I are reviewing our products compliance with IEC 60601-1 and need verification of our millijoule calculations. Our product outputs (up to) a 240v bi-phasic square wave, 240mA and ...
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0answers
39 views

make arduino start when a line is broken

simulate this circuit – Schematic created using CircuitLab Hi. I'm trying to build an anti-theft project. Where if you break a thin wire connexion, It should power ON the arduino and let it do ...
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0answers
149 views

Any specific precautions should be taken when using 2x AA LiSOCL2 batteries in parallel?

I am working on the wireless sensor design and one of the sensor is such that it needs to be kept ON through out the operation and it takes supply of 3V and current of about 100uA, which I think is ok ...
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0answers
55 views

Converting a 24v bldc to 12v

So I have been designing a brushless motor and the circuit that drives it is based off of this Texas Instruments one here. The only problem is that this circuit runs off a minimum of 24v. I would like ...
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0answers
32 views

Alternating between charging two solar cells

I am designing a boat that is operated by two solar cell banks which in turn charge two separate batteries. I would like to run the boat with one bank while the other is charging, and once the one ...
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0answers
235 views

Power issues SIM800l through mosfet

I've got some issues making a SIM800L module to power up correctly through a mosfet. Parts: 2x LifePO4 batteries in serie (6.4V 1800mAh) 1x LM2596 DC Converter (Converts to 5V and able to peak at ...
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522 views

Peltier Driving Circuit

I am driving a peltier (thermoelectric heater/cooler) using a DAC (MCP4725), Arduino mega, quad-opamps to shift/invert the DAC voltage (LT1885) and 4xOPA549 (2 per peltier). I use PI control and ...
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0answers
188 views

LTE vs 3G power cost at low speed

I am currently working on a device in which I need to implement internet connection. For that I intend to use a GSM module, for example this one: SIM5320. This is a 3G module. I have been reading ...
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0answers
117 views

Electrical power in piezoelectric transducer

This question is from the book Diagnostic Ultrasound Imaging: Inside Out By Thomas L. Szabo, regarding the power flowing into the piezoelectric ultrasound transducers. In chapter 5 (transducers) page-...
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77 views

Power amplifiers and maximum output amplitude

In the following circuit, what would be the maximum sinusoidal output voltage amplitude \$V_{omax}\$ which would yield a symmetrical sine wave without distortions when no load is connected? I know the ...
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84 views

i want to operate a normal 220V/50hz Air conditioner at 115V/400HZ system

I have a AC inverter board . in the start ( imean before converting AC 220v to DC 310v ) a filter LC pie filter is used . as we know the operating voltages of AC is 220V/50Hz for normal air ...