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

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-4
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0answers
20 views

I need an external rechargeable power supply to use with a powered 2500 watts portable speaker with an ac input [on hold]

what external rechargeable portable power supply do need to run a 2500 watts 15 inch portable speaker?
0
votes
0answers
26 views

Measuring generated power

I am using a piezoelectric material for energy harvesting. I want to make a portable device that can be mounted along with the pzt which displays how much power is generated from the vibrations.
1
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0answers
58 views

range of transmission line?

I am not electrical engineer by profession. So, accept my apology if my question sounds stupid. I am simulating a situation on computer where electric power is being send from one point to another ...
-5
votes
0answers
22 views

Switching to a Battery backup when one battery runs out automatically . [on hold]

How do i design a circuit which switchs to the backup battery whilst the load (bulb) remains on without going off during the automatic operation and as the backup battery kicks in the discharged ...
-10
votes
0answers
60 views

What industries in EE are hiring right now? [on hold]

So I heard that the power industry is hiring which is true. I'm a rising senior and I've taken a few courses in power. I also have an internship this summer in the power industry. My focus this whole ...
-4
votes
1answer
49 views

GPS receiver component power consumption

I am currently stuck on an assignment where I must state what main parts of a in-car GPS receiver (in this case, the signal amplifier and the screen are what I am concerned with) consume the largest ...
2
votes
4answers
71 views

Moving two elements from series to parallel

I got a small pizza oven with two elements (top and bottom), they are rated 115V 600W and they are connected in series, as we have 230V in Europe. Everything works fine, but I would like to control ...
1
vote
2answers
67 views

Power dissipation

In electronics, we always calculate power dissipation of components and devices all the time. I understand why we do this (heat issues and power supply), but there is something I never really quite ...
0
votes
1answer
45 views

Strategy for powering surveillance cameras

I would like to install 16 surveillance cameras All the cameras are connected to a DVR, 25 meters away (at most) All cameras are powered by 5V-DC, around 3W-6WS for each camera. I have two strategies ...
1
vote
1answer
52 views

How can I power 7 IL151 5mm Clear White LED leds for a sculpture in a series circuit?

I am in the midst of planning a sculpture. The sculpture will require 7 IL151 5mm LEDs with a forward voltage of 3-3.5v . I have NO experience in electronics and I've been looking around and people ...
0
votes
0answers
34 views

How can I know if this USB hub can be supplied separately?

I have this usb hub: It's originally from a laptop cooler, but I'm using it for my project (DIY tablet). This hub has 2 plugs for the fans (I don't use them) and a principal plug (the big one) with ...
1
vote
0answers
46 views

Is it not unsafe for a laptop to hibernate/suspend while an SD card is mounted? [migrated]

Note: I'm asking the question here for I suspect what I've been thinking is a bug in Linux SD card driver actually is an electronics (engineering) issue. Context I have been witnessing for years my ...
-2
votes
0answers
44 views

Calculating the required power of a motor [on hold]

I have following parameters: Weight of car: 200 kg Required speed: 20 km/h Now what will be the required power of motor to drive it as well as the torque?
1
vote
1answer
79 views

How to amplify a very small signal

I am trying to wrap my mind around very small signals; what they mean, and how to amplify them. For example, here is a screenshot from my cell phone. Notice the signal level received is -97dBm. ...
0
votes
1answer
61 views

Wind- Powered phone charging bike rig

I have a 6V motor and another coming on the way. I am trying to create a phone charger on my bike using these motors with propeller blades. I will mount them on my bike and be able to ride and charge. ...
0
votes
2answers
87 views

When building world devices what wall voltages should you expect?

I want to build a dishwasher safe toaster (more details in other questions), So Simplicity of design is a must. Fortunately toasters are among the simplest of electrical devices consisting of nothing ...
0
votes
0answers
31 views

Dual Power Supply Failsafe Logic [duplicate]

I need some help wrapping my mind around the following issue: I have one device that I want to be powered by a main power supply (18V), however in the case the power line drops (e.g. gets ...
2
votes
2answers
119 views

How to adjust linear voltage regulator equivalent?

I'm attempting to build a linear voltage supply. (I'm not touching the mains yet.) My first thought was to use an adjustable linear voltage regulator. Unfortunately, I found that linear voltage ...
0
votes
1answer
117 views

LED indicator for DC voltage

I am planning to using a buck / boost converter to run a DSLR camera from my USB powerbank AND other power sources. For that module I want to build with the buck / boost converter, I need a simple LED ...
2
votes
2answers
148 views

Is over charging the phone while using headset risky [closed]

I recently came across a post in social network which was claiming to be a news about a girl getting electrocuted during her sleep with her headsets connected to the mobile and the mobile being ...
2
votes
2answers
75 views

Using multiple current sense resistors in parallel to handle a high current measurement with cheaper resistors

I am measuring the current going to a motor using current sense resistors; however, in order to get a resistor that can handle the proper power, the price goes up way too much. My question is, can I ...
0
votes
1answer
36 views

impedance matching and impedance briging

Why in RF receiver we need impedance matching for maximum power transfer but not maximum voltage? And why there is no Impedance matching or Power matching in audio engineering? Is it depends on the ...
0
votes
0answers
29 views

3 channel vs. 4 channel 120/240 power meter

So I live in the US, where we have center tapped power for residential use, with two hots and a single neutral wire. My question is what would be the potential effective difference in power ...
0
votes
0answers
36 views

Calculate lower-bound for the total average power

I'm studying for an exam and have come across a question question about power lower-bound. In my lectures we have gone through AC peak voltages, \$\sqrt{2}\cdot V_{RMS}\$, I'm not sure if it's related ...
1
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0answers
26 views

PrimeTime PX toolflow

I need to create a cycle-accurate VCD trace of my component, so after various searches on Google I found PrimeTime PX (I don't know if there are better tools, if you know another, can you suggest ...
1
vote
1answer
69 views

Why the voltage of supply got stuck when connected with leds?

I was working with some smd LED's trying to make their V-I curve. For that purpose, I connected two segments parallel to each other each containing two leds as shown, to a regulated dc power supply ...
0
votes
1answer
43 views

Using a capacitor to properly power a servo

I recently attached a servo to my Arduino for the first time. I ended up needing a 470uF capacitor wired like this tutorial shows because my servo was freaking out and causing my laptop to throw ...
1
vote
1answer
60 views

I don't understand transformer power ratings

I'm befuddled. I have a wall wart power supply that supplies 65W (it's for an Intel NUC). I'm interested in building my own power supply that will put out... several different voltages and currents. ...
0
votes
1answer
50 views

12V Low battery indicator that has minimal power draw

I'm wanting to make a simple low battery indicator for 12V SLA battery - just an LED that lights when the voltage gets below a certain level. What sort of power would a circuit like this ...
0
votes
0answers
39 views

Can I use a single power supply (as in, I plug going into the box

I am trying to put together a headless audio player. In my little wooden box, I will have: A Raspberry Pi (5v DC, micro usb) A DAC Board (5v DC, 2 pin jst). This can be powered from the Pi but I ...
-2
votes
1answer
66 views

Is it possible to have all vehicles run on electricity? [closed]

I read that Elon Musk thinks all vehicles should run on electricity instead of gas but is it even possible? What about large vehicles like buses, trucks, bulldozers and other heavy machinery? What ...
0
votes
0answers
53 views

12V / 3.3V soft power switch circuit

Based on the following circuit I would like to build an MCU-controlled latching power switch that switches 12V instead of 5V while still being controlled by 3.3V (tolerant up to 3.6V) GPIO pins of an ...
-3
votes
1answer
47 views

roland micro cube fuse? [closed]

My power supply fried one day. While troubleshooting (like a fool) i twisted the cap to the t800 ma 250 volt fuse? I guess that's it. Its soldered on the board. I pulled the cap off and the glass ...
-1
votes
1answer
49 views

Power supply issue with LM384 audio amp

I made an audio amp using the LM384 : My soldering skills aren't great but eventually the circuit itself doesn't look too bad. To power it, I used an old laptop power supply (18.5VDC - the datasheet ...
1
vote
1answer
40 views

How to estimate solar panel output as a function of solar radiation

Apparently, according to EarthScience.SE, the measurement of how "bright" a given day is, is measured in units of kWh/m^2, known simply as "solar radiation". ...
0
votes
1answer
63 views

Understanding Royer oscillator (for wireless power transfer), (specially mosfet gate driver circuit)

I need to understand how exactly this circuit works, there is not much references and books on those circuits, they're used as "power" oscillator for DC AC conversion for wireless. i finally found ...
1
vote
1answer
53 views

Measuring P and Q of house appliances

In order to obtain Power-Voltage characteristic of domestic loads (coffeemaker, microwave oven etc) I need to measure consumed active and reactive power at vooltage range U=[0.9-1.1]Un. Is there ...
0
votes
0answers
25 views

Limit large currents in a small space?

I've built a variable voltage bench-top power supply from an old printer adapter. I cut off the output wires, and soldered in connections to a buck converter module and a potentiometer. The limit of ...
0
votes
1answer
72 views

misunderstanding from definition of SNR

We know that SNR is defined as "power" of the transmitted signal to the "power" of the noise. In practice we transmit time limited signals (for simplicity consider the case that there is only one ...
2
votes
1answer
69 views

Is there a simple way to DIY a coaxial male connector?

I have a 12V power supply that has a female coaxial plug like the one on the right in this image: I rigged something up with tinfoil just to see if it would work, but it's not ideal at all. ...
1
vote
1answer
59 views

how big my track should be to handle this current

I've read before that each 1 mm\$^2\$ of copper can handle up to 1 A. Is that true? Is there an easier formula than the one used on online calculators that requires temperature and such? To give more ...
0
votes
1answer
66 views

Use 4-pin S-video cable connector on RGB LED?

I'm hoping to make some 4-pin RGB LEDs (R, G, B, GND) easily hot pluggable, so I'm wondering if 4-pin S-video connectors could be used. Now, 2 of the pins on a S-video connector are GND, so would ...
-1
votes
1answer
59 views

Current consumption calculation and also battery life calculation [duplicate]

I'm a newbie, I need to know how to calculate the current consumption of circuit and also how do calculation of the battery life according to the circuit's current consumption? I'm using Li-Po ...
0
votes
1answer
33 views

Question about clearance/pad diameter and PCB design

Sorry if this is a silly question but I am relatively new to Eagle and I am 100% new in dealing with high powered PCB design. So, I am making the footprint for the LEM LV 25-P voltage transducer seen ...
0
votes
1answer
81 views

PCB - High current PTH

Some power boards are failing a high current (lightning) test where an MOV lead is used to transfer the current to the bottom of the board - see MOV lead and pad attached. The issue seems to be that ...
-1
votes
1answer
42 views

What is a safe level of electromagnetic radiation measured in terms of received signal strength indicator (RSSI) e.g. -26 dBm?

We know that the laws of our countries set the regulatory limits of EM radiated power based on the EIRP transmit power of the antennas of devices. However, the received incident power is more ...
-2
votes
1answer
50 views

Battery charged over USB and powering DC motors

I need help with figuring out how to power DC motors in my project. I need to power two 12V DC motors (they are connected in series) that will be controlled with momentary switch. The idea is to have ...
3
votes
1answer
56 views

ATmega ADC input channel analog vs digital power

The data sheet of the ATmega48A/PA/88A/PA/168A/PA/328/P states that ADC input channel 5 and 4 use digital power, while ADC input channels 3-0 use analog power. Does this mean that ADC 5 and 4 use Vcc ...
0
votes
1answer
44 views

Calculating total power draw of device (camera) and accessories

I work with cinema cameras and at any given point the camera will be adorned with a number of accessories e.g. Monitor, Follow Focus Motors, Cinetape etc which are being powered by ports on the camera ...
1
vote
0answers
88 views

I have made a simple Input protection circuit, it works most of the time. But is failing now. Confused

Its working in Spice, but I dont know why is it keeping on failing when i give and input of 24V, but when I ramp it up a little bit,its failing.. The schematic and the waveform is given below: