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

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1answer
39 views

Determining which power supply is connected to our circuit?

I am designing a small dongle that will have features either enabled or disabled as a function of the supply voltage. I want the device to be low-power and run, for the most part, off a 3V coin-cell ...
0
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0answers
15 views

garbled characters display in Power System Analysis Toolbox (PSAT)

I've tried many versions, it still didn't work, does anyone else have similar problems before? Thanks very much!
0
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1answer
34 views

How battery-charger system in mobile phones and laptops works?

It was 5 am in the morning stuck at McD and waiting for the train with my friends. All out of nowhere I asked them this question that I have been thinking about for some time. How this ...
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0answers
41 views

Need help picking up low cost efficient power supply IC/PCB mount for microcontroller project [on hold]

I am new to this field and after researching I found the requirements I am looking for. Now I am looking for solution with following requirements. Input 120-240 AC (universal) Output min-200mA, ...
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1answer
32 views

Power Supply. DC to DC inverter [on hold]

I need a schematic of a circuit to convert low voltage DC with high current to 12-13 V DC, here is the source: Voltage = 0.2V DC, current = 1000A, Please advise, Regards, Thomas
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2answers
107 views

wiring a 3 position toggle switch for two devices?

I am building a plastic vacuum molding device that requires a heating source and a vacuuming source. For safety reasons I want to install an On/Off/On toggle switch so I, or whomever, am forced to ...
2
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0answers
30 views

Low Pass Filtered Noise Power Spectra, Showing Low Power @ Lowest Frequencies

White noise is being passed through a voltage follower, then filtered through a simple first order low pass RC circuit (C=0.5 micro Farad, varying resistance between 2k-10k, ohm depending on RC value ...
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3answers
59 views

Reconciling V, A, iPF and kW for my air conditioner

On the energy meter installed by my utility company (a 1-year old digital Landis+Gyr), I noticed the following steady-state readings when my inverter air conditioner (with a variable speed compressor) ...
0
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1answer
33 views

Replacing Power Board European Samsung TV's with an asian one [on hold]

After a lightning strike, my European (Model UEXXC..) Samsung Tv is dead. I searched for a new Power Board and I found out that european boards cost 4 times more tha asian ones( Model UAXXC..). ...
1
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1answer
42 views

TVS unidirectional vs bidirectional in Hbridge

I have used this circuit (I found online last year) to drive big dc motors without much thinking but with great success. http://obrazki.elektroda.pl/4961105700_1437649469.jpg : - But yesterday I ...
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1answer
320 views

How not to waste power with digital inputs?

I am trying to make simple gates with n-MOSFETS, yet I'm not sure how to actually do physical gate inputs correctly. At first, I tried this (a single-pole, single-throw switch from +5V to gate). ...
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0answers
25 views

Toshiba 29L1350U no signs of Power [closed]

I have a toshiba 29L1350U that has been in a spare room for about a year. Never used it. Recently it got moved to a bedroom where it will get use and it came on fine. I had plugged a Fire TV Stick ...
1
vote
1answer
77 views

What happens in the Arduino power supply schematic?

I was just looking at the power supply part of the Arduino Uno, but I am a bit confused: 1) Why the opamp LMV358 with VIN as input (USA)? 2) Why the opamp LMV358 with SCK as input? 3) Why an LP2985 ...
1
vote
0answers
37 views

Leaking power off of a coil

I am trying to make a wireless door opener by adding a small Arduino with a relay switch into our home phone. Unfortunately, that home phone operates without a power source, it has wires for audio and ...
0
votes
1answer
44 views

Customized Digital Clock(two power sources)

I am quite newbie in electronics. Recently I bought a Digital Alarm clock and tried to customize it by adding DC motor wheels . Idea is to set an alarm , when its alarm time apart from sound it should ...
0
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0answers
20 views

What is the critical point of saturation of distributed power on the power system?

With the benefits of distributed power/generation widely known, it is also known for the disadvantages of it two-way power flows considering typical distribution systems are only designed for one way. ...
-1
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0answers
28 views

Computer power supply fault [migrated]

This is my first post to the site; it's been a great resource to me in both my professional and personal lives. It's about time I registered! So I went to boot up my desktop this morning and nothing ...
1
vote
1answer
60 views

Can I run my audio mixer off the battery powering my amplifier?

Background info: I have a small battery powered 25W amplifier/speaker combo. KustomSound CB25X, with two 6V 4.5Ah SLA batteries wired in series for 12V. Fully charged, the voltage seems to be close ...
1
vote
1answer
53 views

thermal knife power supply (part 2)

This is "part 2" because my original question has only brought up more queries that i am unable to solve. The first part can be seen here for any who are interested: "Hot-knife"/Thermal ...
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0answers
52 views

200W LED Driver [closed]

I need to power up an LED system that requires between 32V and 36V at 4.9A I am having hard time to find the proper driver to lit up this system. The ideal would be a driver that allows for dimming ...
0
votes
1answer
34 views

TSP65070 and OMAP 1V8 pull up to 2.7V

I want to use the TPS65070, the power solution for DSP to power the OMAP L138, but i read in the errata sheet of the OMAP L138 OMAP L138 Errata page 25 that the 1V8 power supply can pull up to 2.7V ...
0
votes
2answers
65 views

Switching regulator (TI LM2678) not working on load > 100mA

I am a (joung) programmeer and I recently began studying some electronics&AVR programming. I am trying to use a step down voltage regulator (LM2678-5.0) to transform battery voltage (9/12V) into ...
0
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2answers
51 views

How to add solar DC output, Wind DC output and Fuel cell DC output to create a DC bus

How to add solar DC output, Wind DC output and Fuel cell DC output to create a DC bus. My doubt is, Is it possible to connect the outputs of different type of power sources(considering the DC voltage ...
1
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1answer
56 views

Phase Sequencer

I have 3 phase voltages entering into my PIC ADC (3 different channels ) through a voltage down scaling circuit and I have successfully calculated their rms values inside my controller.Know I want to ...
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0answers
35 views

Proteus Sine Current Source Simulation Issue

The circuit below is being simulated in proteus isis v7 Current Source has Amplitude value 5A (as asked by Proteus). Two Resistors of values 3 ohm each and then there are two AC voltmeters ...
0
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1answer
61 views

Power supply automatically disables before the fan has time to reach the minimum current

I bought a power supply, which provides 5, 12 and 24V. The issue is that it has a disable if there is not a minimum current on the output after a certain amount of time. After testing with a resistor, ...
0
votes
1answer
44 views

Connecting the voltage sense screws of a power supply (wire gauge to use?)

Very often I see high wire gauges (i.e., very thin cables) used for the wires that connect a test circuit's voltage input terminals to the sense screws of a power supply. I would have thought that you ...
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votes
2answers
29 views

Estimating battery capacity remaining from SLA connected to motors

I have an SLA battery, at say 10 Amp-Hours, connected to 3 high power motors. Each motor can draw up to 10 Amps each (worst case / max power). Using Q = It as an ...
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votes
2answers
47 views

power supply regulator output current

Here i have attached basic power regulator block diagram. The voltage regulator input (Vin) get 5V from adapter and gives ouput as 3.3V maximum of 3Amps load current.My question and understanding is ...
0
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2answers
45 views

Apparent power meaning

As far as i have read v(rms) is a dc value and i(rms) is also a dc value and apparent power is multiplication of both of them.so,can apparent power be represented as dc power absorbed by an ac ...
6
votes
1answer
317 views

Is there a reason for the shape surge arrests have?

Why do surge arrest typically looks like this ? I found one of the reason is to prevent ingress of water by using slippery rubber material but it does not explain the reason for the shape of the ...
0
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0answers
35 views

12/15V 500mA Current Limiter for Supercap Charging

Long time reader finally asking for some help. I have a 10F equivalent capacitive load that needs to be charged to 15V. My issue is that I only have a max draw of 500mA at 30V available (seemingly ...
0
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2answers
85 views

constant voltage drop at (relatively) high current

I'm making a power supply using some decade switches and resistors. The idea is to dial a voltage, much like a resistor substitution box, but get a voltage out instead of a resistance. I'm using the ...
0
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0answers
69 views

Can I wire 110v solenoid project straight to mains power?

I'm making a arduino project where the 5v current switches on/off a relay to power a solenoid. I've just bought a 110v 50/60Hz tractive solenoid and can't figure out the right way to power it. I'm in ...
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1answer
60 views

Frequency, Power, Radiation [closed]

Are GSM cell towers dangerous to people who live in their environment? What radiating power of device is starting to be critical to environment? Is that radiation regulated through some laws? Which ...
0
votes
1answer
55 views

12v-4.2v power supply design?

I have a Sony A7R camera and i want to make a power supply that runs of a 12v lead acid and has a output of 4.2v so i can take long time lapses, i don't know much about electronics so i came here to ...
0
votes
1answer
92 views

Voltage drop when load is applied

I have four 200AH batteries connected in a series-parallel form. These batteries are charged using an alternator mounted on a running engine. The purpose of these batteries is for lighting. There are ...
0
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1answer
38 views

Can polarity be reversed to effectively reverse the output of its intended/motored function?

For "simple" electric items/tools with motors -- ones without complex electronics -- can the polarity be reversed to effectively reverse the output of its motor? In particular, I'm wondering about an ...
0
votes
1answer
35 views

trying to increase current output of a generator

this is my first time posting here also I'm very new to electrical engineering. i am building a pull cord (like a lawn mower) human powered generator and I'm looking for ways to increase the current ...
0
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2answers
112 views

LED lighting project wiring Questions

let me begin by thanking anyone and everyone for any help. I have a serious lighting project and am likely getting very ambitious. I am trying to wire up a series of WS2812 LED strips. Each 2 ...
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0answers
37 views

Raspberry Pi Circuit Problem

I am currently trying to build a robot using raspberry pi. As a power source I am using an battery pack which provides 1.5 A at 8.4 Volt. I set up the circuits so that the power source was connected ...
0
votes
1answer
43 views

Calculate Power of 3 Phase HVAC Unit

I have an HVAC unit and I know the phase 1 current, phase 2 current and phase 3 current. I know the voltage of the unit, from this, how can I calculate the power used by the entire unit? Further ...
0
votes
1answer
31 views

Given the dynamic and static power consumption how does one determine the total power for the capacitive load?

I get that the capacitive load is determined which is also indicated by this question: $$\frac{Power}{Voltage^2 \times frequency} = Capacitive Load$$ However, I am not sure how power (which is ...
0
votes
1answer
41 views

USB 3.0 power levels on USB 2.0 device

Is it possible to negotiate a USB 3 power level, such as 900 mA, if the device is connected to a USB 3 port, without being a device capable of the higher speeds? I'd like to use this higher level if ...
-5
votes
1answer
96 views

Is it possible to use a wattmeter to switch a power outlet? [closed]

Can I use a wattmeter to switch a power outlet? My idea is to connect the wattmeter with a relay and when there is current the relay turns on like the thing in a master-slave power outlet. Is this ...
2
votes
3answers
164 views

Op-Amp + MOSFET = Constant Current Power Source (?)

I'm trying to make my first circuit from Horowitz and Hill- a constant current source that sits above the load, and can (hopefully) source 1A. I decided to use the components I had on hand- an ...
1
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2answers
186 views

Passive POE: Need 5V @ 2A at the destination

Having a bit of trouble finding the right information on google, and I'm worried I might fry some cables so I thought it best to ask some far more knowledgable than myself. I want to connect 2 or ...
0
votes
1answer
167 views

What is the name of this cable?

What is the name of the next cable: (source: http://www.e-shetach.co.il/images/itempics/24to12_large.jpg) Those are 2 examples of how it looks, can anyone tell me the name of it? Thanks in ...
0
votes
2answers
101 views

Powering microcontroller by bypassing ldo regulator

I'm working on a circuit design with a microcontroller that runs on 3.3V. I'd like to be able to power it either through a 3.3v supply or a USB port. I'm using an ...
0
votes
3answers
48 views

4-20mA Loop powered DAC

I was selecting a DAC for HART network and in the process I came across two terminology. 12-/16-Bit, Serial Input, 4 mA to 20 mA, Current Source DAC AD5420 and 16-Bit, Serial Input,Loop-Powered, 4 ...