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

learn more… | top users | synonyms

-1
votes
2answers
31 views

Ideal Operational Amplifier excercise

Having an ideal operational amplifier on the circuit below, i need to find the power at R3. Can you help me? Isn't it 0? I couldn't find anything similar on my books.
0
votes
3answers
65 views

How to increase the rated output voltage/current by connecting multiple op amps?

Is there a way to increase the power output from connecting multiple op amps? My guess is that connecting the op amps' output in parallel will increase the rated current, and connecting power ...
1
vote
0answers
73 views

How to switch between two 220VAC motor power supplies?

I am not an electrician, electronics engineer or anything that will relate me with your interesting profession, but I am a Project Engineer, Mechanical Engineer, etc. and I am working in my spare time ...
0
votes
1answer
37 views

Powering a 4-Pin stock CPU heatsink fan with an external power supply

I have scoured this website and the rest of the internet looking for a solution to my particular issue, but as of yet I have not found an answer. If this is a duplicate question I am sincerely sorry, ...
0
votes
2answers
67 views

How can I calculate DC motor continuous current?

I have some information for a brushed DC motor: ...
2
votes
1answer
60 views

How to measure energy distribution

I want to evaluate the energy flow in a battery powered system. So when the system runs a specific task the energy distribution between the different loads can be obtained ( similar to a Sankey ...
-4
votes
1answer
35 views

If I have a 12v battery which is connected to an inverter [on hold]

I am a Project Engineer which like to explore as a hobby other areas and I have a question for your expertise to advice me to follow the right way, here is my idea & questions: I want to use a ...
0
votes
2answers
36 views

How to decrease 83v 17ah DC battery to 72v?

I purchased a 72v 20ah battery pack for my electric bike. When the battery came, I tested the voltage and amperage and found that the battery came to be ~83v and ~18AH. My bike's controller can't ...
0
votes
1answer
31 views

Arduino Yún and battery life

I am working on a small project that requires an Arduino (Yún?) to be powered by battery and connect to wifi. I am thinking of using the Yún since it already has wifi abilities. My question is: What ...
-1
votes
0answers
10 views

Phase Sequence Relay Operating Principle

Can anyone kindly explain how phase sequence relay works? I searched it but could not find an adequate answer.
1
vote
1answer
38 views

How can I tell how many watts a toroid can transfer?

I am trying to get general idea of what size of cross-sectional area I would need on a toroidal core to use it as a step-down transformer of a given power rating. I am aware that the answer depends ...
-1
votes
2answers
78 views

Right half zero in boost converters [on hold]

When we increase the duty cycle in boost converters, why does the output voltage first decrease and then increase. After the time associated with the right half zero has elapsed then output voltage ...
3
votes
3answers
263 views

Correct Way to Limit Op Amp Output Current

I'm planning to use an AD817 op amp in the output stage of my function generator (datasheet). I'm worried about how the part would stand up to a short, so I ran some simulations. The simulation below ...
1
vote
1answer
51 views

transmission lines voltage drop

When trying to explain the need for high voltage in transmission lines, I came across a formula in one of my old courses: A transmission line is considered, and between the generator end and the load ...
0
votes
0answers
25 views

battery augmented power supply

I have a project that requires a 12v power supply. 95% of the time the current draw is only a few amps. As such a pc power supply is sufficient. However occasionally the system requires 200amp for ...
1
vote
2answers
32 views

per-charge cost to charge a battery bank at $0.10/kwhr

Am I forgetting my EE knowledge? I have a 10400mAh battery bank at 3.8v so it's ~40kwhr? $4 to charge once? assuming perfect charger efficiency and no power loss to heat
-4
votes
1answer
65 views

Prevent power adapters separated from the device it was purchased with [on hold]

Why are there no standards for products sold with external power-supply specifying proper labeling to match the device and its power-supply? A manufacturer of an external hard drive uses a generic ...
0
votes
2answers
67 views

Implementing Safety Shut-Off Relay In Project

I am working on a project which I have poured lots of cash into that involves water, pressure and electronics in very close proximity of each other... Lately, I have been considering adding some ...
0
votes
1answer
44 views

Running 2 5V USB battery power packs, Can I use them in parallel

Can I run two 5v power packs in parallel to give me more mAh's (Time)? Or will one try and charge the other? Example I.E. connect both 5V lines together, both GND lines together to my device
0
votes
0answers
22 views

symmetrical components and power conservation?

My understanding of the method of symmetrical components is the following: An unbalanced three phase system (voltages, currents etc.) is split into three balanced sets; zero, positive and negative ...
-3
votes
0answers
57 views

Does a switched on power socket consume electricity? [closed]

Let's say I have a TV and a power socket. The TV's switch is open and the socket's switch is closed. Will this outlet consume electricity?
0
votes
1answer
34 views

Protect Beaglebone Black from Power Outage

I am using a BBB (Rev C) as a web server, powered by a 5V power supply connected to the 5V jack. I read in several locations that disconnecting the power supply to turn off the board can damage the ...
0
votes
0answers
20 views

Powering a 5V device from one or more sources

I'm building a circuit and need to power a PICAXE IC from one of two possible sources - a USB 5V connection (which provides power for the Adafruit Powerboost 500 charger), or a Raspberry Pi, which ...
0
votes
2answers
43 views

USB power in Parallel, increasing the maximum current using a Y splitter idea[POWER ONLY]

When you connect batteries or power sources of the same voltage, in series, the voltage adds together. When in parallel the capacity of the two add together. Ive seen a few usb>sata cables in which ...
0
votes
2answers
51 views

What sized motor could spin ~2lbs?

I am working on a prop for a film -- I have to make a sign spin in a circle (simple attachment to a motor) and have variable speed. I know enough to wire the thing, but am having a hard time getting ...
-2
votes
0answers
25 views

Power flow on branches using matrix algebra

Having: S: The vector of power injections at each bus. V: The vector of bus voltages. Y: The circuit admittance matrix. A: The branch-bus connectivity matrix. ...
0
votes
2answers
27 views

PLC For MV Networks

Can power line communication work over both live LV (+-230V) and MV (11kV) conductors? Is there hardware available that makes this possible? Up to what voltage is power line communication possible?
0
votes
2answers
49 views

DC Supply Load Dummy based on NPNs

I am fixing an old regulated load dummy that I use in my workspace. It was a mess and I want to modify its regulator side. My question is: will the circuit showed in the image work properly? If you ...
2
votes
1answer
298 views

Whats the overrall power available from two PSUs in series?

Consider this circuit: PSU 1 is rated at 100w, PSU 2 is rated at 200w. How do I calculate how much power is available to the load, given the mis-matched power supplies?
1
vote
1answer
30 views

KiCad: Power with hierarchical sheets

I just started trying to use KiCad (complete newbie), and I have a very basic question about using power inputs with hierarchical sheets. Let's say I want a single LED on a hierarchical sheet, while ...
0
votes
1answer
66 views

Power Switching with Microcontroller

I am in the process of designing a device for a uni project. As a requirement, we are required to have a very low power consumption whilst in standby mode. Our plan for this, was to have our 2 x +-5V ...
1
vote
1answer
58 views

Adding a remote switch and battery to a 9 volt dispenser

I have an insecticide dispenser in my shop. The unit is designed to spray a short burst of insecticide once every 8 minutes. I have found I don't need this frequent of a burst and my thought is to ...
0
votes
2answers
41 views

compare high power mosfet for high power load

I'v been searching mosfet for high power load project (DC 110V 100 Amp) and I found Fairchild FDL100N50F (TO-264) with maximum Power Dissipation 2500W. According to data sheet, the Max SOA DC ...
0
votes
1answer
45 views

3v wireless arduino and power consumption

I decided to create another post in order to get feedback for my ideas. I have created a network of wireless sensor nodes which connect to a central arduino with serial connection to a RPi. I ...
1
vote
2answers
166 views

Help me identify this mystery IC? [closed]

I had a bug (yes, a literal bug) decide it would be a good idea to crawl inside my printer and short itself across two pins on my printer's power supply board. I have pulled the board in the hopes of ...
0
votes
2answers
69 views

RF Transmit Power in an ISM band

I was browsing through some OFCOM Frequency Allocation Tables for use on a small project I'm doing. I require the use of some unlicensed ISM bands in the UK, and found that the lowest unlicensed band ...
0
votes
2answers
33 views

Find which wires are what in a sjt power cable

I'm trying to figure out what wires are live, neutral and ground in my computer power cable. I'm getting some weird readings from the wires. ...
0
votes
1answer
91 views

Rapidly switching on and off a 12v power supply, bad idea?

I was just wondering if this would be a bad idea, the power supply is connected to the mains power and would only undergo this at a max of 10 minutes at a time. would this cause any damage to the ...
0
votes
2answers
49 views

RF power limiter

I am interested in constructing my own version of an RF power limiter. There exist models such as the 11930A Power Limiter, but are very expensive. The intended use for the device is to limit input ...
0
votes
1answer
70 views

Few doubts about turning an atx psu into a bench lab power supply [closed]

First, thank you for your time of reading my questions. As the title suggested, my questions are about turning a computer power supply into a lab power supply. I already did my homework and read ...
-4
votes
0answers
38 views

Power Mosfet and IGBTs

Can somebody explain me the difference between power semiconductors and traditional ICs..and within power semis the difference between IGBTs and Mosfets. a detailed answer would be really ...
1
vote
2answers
88 views

Battery life: 2xAA or 4xAAA - which is better?

Which will provide longer battery life: 2xAA batteries in series or 4xAAA batteries in series regulated to 3V via a voltage regulator or buck converter?
1
vote
2answers
107 views

Help in the design of a super low power device

I'm building a wireless device that have to last with batteries as long as posible. The device has an rf module with a microncontroller that manages the control, that part is bought and works fine. ...
1
vote
2answers
40 views

Calculate power supply for step down modules

i'd like to build a system in which there will be step down modules that get their power from an ac-dc converter. there are 5 modules connected to the ac-dc converter (each of them steps down to ...
-3
votes
4answers
83 views

Can I power a 110VAC heater with 230VAC [closed]

Can I give power supply of 230VAC to 110VAC heater? What is the effects on giving higher voltage on heaters?
0
votes
1answer
46 views

A single pump controlled by a VFD

We're testing a 110V single phase Variable Frequency Drive(VFD) connected to a single pump having randomly let's say: R= 10ohm, L= 50mH. And I am putting these numbers to fiqure out the relationship ...
1
vote
2answers
71 views

Two power supply units, equivalent settings, different results, why? [closed]

I recently bought a 3d printer which runs on a Melzi v2 board [http://reprap.org/wiki/Melzi]. It came with a 12V 20A power supply unit (multimeter readings showed values ranging from 11.8V-12.1, im my ...
2
votes
2answers
81 views

What resistor should I buy (More than 2kW peak power)

Im using a resistor (68Ohm) to discharge a capacitor bank rated at around 400V. This is the graph of the current and the power in the resistor, as you can see there is a 2KW (4.5A) peak. But it's just ...
-2
votes
2answers
66 views

Starting current of an induction motor

How to calculate the Starting current of an induction motor if I have the power in kilo watts and the voltage? I have looked up formulas , but I got confused. I calculated the full load current by ...
0
votes
0answers
32 views

Circuit error: Possible reverse current in the circuit

Imagine the system: 1. Power supply connects to CAN EGSE 2. Through DC/DC converter, EGSE provides converts 28V to +15, -15, and 5V outputs 3. The outputs go to the module Note:EGSE provides CAN ...