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

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0
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2answers
12 views

Three phase Motor rotation

Is it possible that a three phase motor still spin in the same direction it was even after the phases are interchanged.
3
votes
2answers
49 views

Help to join 3 resistors in parallel into 1 (power equiation?)

I want to join 3 resistors connected in parallel into one. Like this If for the total resistance I use Rt = R/3 But what about the power of them?
0
votes
1answer
93 views

Does 3.3v ground and 5v ground connected will affects circuit?

I have a wifi transciever(ESP8266) which should be connected to 3.3v and microcontroller connected to 5v(PIC16). For establishing the communication between the microcontroller and wifi they should ...
0
votes
3answers
49 views

Application of power factor correction

If the reactive power that is induced by an inductor that is connected to a resistor (a lamp) is corrected by a capacitor, does that mean that I get more light out of a lamp? The way I see it is ...
3
votes
1answer
49 views

why Commutator power capacity is limited

A commutator's power capacity is said to be limited to a few megawatts. What are the reasons limiting it? I thought it could be like brush resistance and spark strength. What is the maximum voltage ...
-4
votes
1answer
73 views

How much current does IC7805 device draw?

I'm wondering how much current does IC7805 regulator draws in order to drive 1.5A load. Thanks
0
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2answers
48 views

polarity of dc power require by electronic device

How can the polarity required of device marked 7.5V 1.2A dc be determined, i.e. how to know if the center of the plug on the device's box is positive or negative I do not have the original charger. ...
-2
votes
3answers
72 views

Power meter and electric bills

Can anyone explain to me how the power meter can differentiate between the reactive power and real power? If power is current times voltage, can we assume that since reactive elements give back the ...
0
votes
3answers
175 views

Electric bill for reactive power

I have read that if you don't unlug the charger from the socket after charging your phone, although it is not connected to the phone, it still consumes power and your electricity bill adds up. On ...
-2
votes
2answers
68 views

How power meter works for residential buildings?

If power is current times meter shouldn't the overall resistances and inductances and capacitances of my house appliances be known so the power meter could calculate the power. I look at my house as a ...
0
votes
1answer
44 views

Need to identify this cable

I recently bought this product from Amazon, but need to get a splitter for the 20V output. I need to know what to look for though, and cannot identify what kind of cable this is / what to search for. ...
2
votes
4answers
62 views

What is capacitance required for this 3 phase rectifier

In the diagram above I want to know the value and the rating of the capacitor that should be used for good rectification The Line to Line voltage is 400 , and by relation Vdc =(3√2 VL)/pi=(3√2 x ...
0
votes
0answers
31 views

Typical 3g power consumption

What is a typical power consumption of a relatively low power embedded 3g modem (for IOT) during communication?
0
votes
1answer
48 views

Simple lightweight high power amplifier circuit

I'm looking for a way to amplify a 12V sinusoidal signal to drive a set of transducers at ~120V with an overall power of 100W. The quality of the output signal does not have to be good, simplicity ...
0
votes
1answer
34 views

Portable power supply for over 300 ws2812 LEDs (similar to youtube video)

I have an idea fro a project which requires a few hundred ws2812 LEDs to be powered using relatively small battery which can be carried. I was wondering how you could power over 300 ws2812 LEDs ...
-1
votes
1answer
33 views

What telecom satellite data sets require for anomulus propagation investigation

I am going to investigate anomalous propagation like sub refraction, super refraction, ducting and i want to use tale com satellite Paksat1R data in order to check effect of anomalous propagation on ...
0
votes
2answers
87 views

What are the different ways to switch power using a microcontroller (Arduino, Raspberry Pi, BeagleBone, etc.) and what are the pros/cons for each?

I'm using an Arduino to control a 12v water pump for a self-watering plant wall. I'd also like to use the same power supply for both, and probably need surge protection of some kind to avoid spikes. I ...
0
votes
1answer
36 views

Irms to Idc for inductor selection

I'm trying to build a buck converter using one of Power Integrated switches and their online design software lists the inductor rating in Irms. However, most inductors have their current ratings in ...
0
votes
1answer
41 views

max current drawn from an IC or a circuit [on hold]

how do i find the max current drawn from a simple circuit with an IC, few resistors and caps. if it's taken from the datasheet, what current rating i should be looking at exactly? or should i be ...
0
votes
1answer
48 views

Using european telephone cables for own DC power delivery

I have european telephone cables running through my walls to each room, without any connection/socket. Well... we really do not need any hard line telephone connection and I am into DIY projects, so I ...
2
votes
3answers
95 views

solar power ESP8266 microprocessor circuit to turn off when low voltage

I intend to run an esp8266 microprocessor on only solar panels so it is on during the day and off/disabled during low light conditions that do not supply sufficient power. Is there a circuit that ...
1
vote
1answer
54 views

Calculating power with RMS

Suppose I have a rechargeable 70 kWh battery , and I use 120 V rms from my house with a 10 A RMS circuit. To find the max power of this circuit, is it just P = VI, since both the voltage and current ...
0
votes
0answers
22 views

Joining terminals of LiPo batteries

What are the ways to join terminals of LiPo batteries, except using soldering or spot welding?
0
votes
2answers
55 views

Power of a capacitor when is connected to a battery

According to definition of power ( current times voltage) since there is no change in charge, the power stored in a capacitor connected to a DC voltage is zero. Since energy is power times time, ...
0
votes
2answers
76 views

Cable rating - What is the max amp for a 1.5-1.75mm cable?

I have a new hob (magnetic induction plate). It requires 7200W/32A. The power grid's voltage is 230V (Europe). I have already installed a thick cable and I want to use it (it would be difficult to ...
0
votes
1answer
39 views

Harmonic Power Flow

What is the fundamental differences between the conventional AC Power Flow (CPF) & Harmonic Power Flow (HPF)? Is HPF simply a combination of CPFs at different frequencies? Instead of finding the ...
0
votes
2answers
60 views

Power in AC circuits

When I look at the graph of the power in AC circuits versus time (not the average power I am talking about the instantaneous power) it goes from a negative value to positive. On the other hand, I know ...
-2
votes
0answers
34 views

Laptop power button not working. Where should i look? [on hold]

Hello i'm trying to fix my laptop's power button. The button is attached into USB adapter module. I checked switch and all connecting pins to motherboard with tester (connection was solid and well). ...
0
votes
0answers
37 views

Solor Panel and Super Capcitor

I need some help trying to figure out the sizing needed for a solar panel and super capacitor. The overall design is a solar panel hooked up to an energy harvesting chip that charges a supercap. The ...
0
votes
1answer
63 views

P channel mosfet battery charging/power selection circuit help

I am a hobbyist and new to this, but I am not sure if my circuit it right. The goal is: To power the rest of the circuit from a DC source, a USB, or a battery, in that order. When there is no DC or ...
4
votes
2answers
106 views

Buck Converting Voltage, to Switch Original Voltage

I'm learning electronics, so I want to sanity check this approach in case I'm missing something. I have an arduino (at 5V) controlling power to a set of lights at 12V, via a mosfet. This is all fine, ...
0
votes
2answers
62 views

Resetting a microcontroller with a button connected to Vcc

I would like to have a way to reset my PIC by removing power from the chip. My hacker self thinks that the simplest way would be to add a resistor between the output of my LDO and Vcc on the PIC, and ...
0
votes
1answer
35 views

Making a battery pack out of 8 cells in 4S2P configuration

I want to make a battery pack of 4S2P using 8cells. Is it better to first make 2 sets of 4 cells each (4 cells joined in series to each other) and then join these 2 sets in parallel or first making 4 ...
0
votes
2answers
53 views

How does the definition of electrical power follow from the chain rule?

Just a small question for clarification. Here's what I know: current I is defined by \$I = \frac{dq}{dt}\$ where q is charge and t is time voltage V is defined by \$V = \frac{dw}{dq}\$ where w is ...
-2
votes
2answers
42 views

How to get a 5-30 VDC trigger voltage from a A/V receiver? [on hold]

My old A/V receiver had a switched 120VAC outlet that powered on when the receiver was powered on. My new Yamaha A/V receiver (and no new receivers, evidently) does not have a switched 120VAC outlet. ...
0
votes
1answer
74 views

Power supply logic design [closed]

I have three power sources that supply voltages from 3 to 9 volts. This will be going into a positive voltage regulator for stable output. If the third source is present it takes precedence over the ...
0
votes
1answer
37 views

LNK304P unexpected output voltage

I trying to understand what problem with next scheme. I have a power supply which should provide +12V but in my case it's only about 5v in output (checked on 1-2-7-8 and Gnd pins). I have tried to ...
-2
votes
1answer
49 views

Bad if I use a Higher power adapter for a keyboard instrument requiring lower power and amps? [duplicate]

Can I use a 13.5VDC 1a power supply for a keyboard that requires a 10VDC 800ma power supply without ruining the keyboard? I was told that the keyboard would only draw the power and amperage it needed ...
-2
votes
0answers
19 views

Parameters associated with power transients

What are the major parameters associated with transients in a power system? I am going to use discrete wavelet transforms for analysing it. So, is it only magnitude, duration and spectral content? ...
0
votes
1answer
48 views

wattage consumption of three phase electric motor

i have a 5 hp motor in my factory . at load, it shows 3.5 ampere consumption ( when tested by a meter). is the consumption accurate? someone told me that 5 hp three phase motor will consume 7.5 ...
0
votes
1answer
43 views

Transformer output connected to another transformer. Measuring 'Real Power' at input of first transformer

I have a watt meter connected to the primary of one transformer to measure power. The output of this transformer is connected to the input of another transformer. The watt meter is measuring the ...
-2
votes
0answers
77 views

Issue with MANUAL-AUTO logic [closed]

As per the circuit I would be able to control the circuit through the manual switch which is connected to the Digital Input of the controller where 5V DC is looped and other alternate command ...
1
vote
2answers
73 views

Power Factor - What is it a characteristic of?

I always thought it was a characteristic of a powered device, rather than the power source. A generator (whether it's a station or a small petrol powered one) does not have a power factor. I've been ...
0
votes
1answer
66 views

Solar panel subsystem project

I am trying to build a subsystem for a project that I am undertaking in university. An overview of the subsystem can be seen in the attached image. The only difference from my subsystem and the one ...
0
votes
1answer
65 views

Adding 2 cooling fans to an amplifier circuit board

simulate this circuit – Schematic created using CircuitLab I'd like to add (2) 5v .41A cooling fans to this Vox bass amp. What Resistor/capacitor combo (R3/C4) would be best?
0
votes
0answers
45 views

Finding the effective switched capacitance in Intel processors

I need to able to calculate the power consumption of an Intel processor using the equation, P = C * (V^2)*f where C, V and f are the effective switched ...
0
votes
1answer
63 views

Power consumed by an LED in a simple circuit

I am in the very beginnings of studying circuits and am a little confused on calculated Power. If I have a 9V Battery, 4 x 10k Resistors and a single LED, how would I calculate the power consumed by ...
0
votes
3answers
121 views

Should I continue with daisy chaining?

I've been daisy chaining power strips and it was no issue until my friend told me it's dangerous. I was using 2 monitors, fan, desktop,55inch TV, monitor speakers, and a phone charger. And he told me ...
0
votes
1answer
46 views

RF cable with DC power cable?

I have a satellite communication system at office running on C-band. The C-band is downconverted to L-band and carried to the l-band modem. With this RF coaxial waveguide/cable, +12V DC power cable ...
0
votes
0answers
38 views

modify computer power supply for higher voltage

On a computer power supply there are some potentiometers on the secondary side. one of them is in series with a resistor that feeds into a VrefMAIN pin on a voltage supervisor IC. When I turn the ...