Where power is a primary concern for the design under discussion. Use the "low-power" tag when that applies.
1
vote
0answers
74 views
Why does my bluetooth dongle use more current when paired then when idle?
I have a bluetooth dongle which is connected through USB to my PC. I wanted to measure the current drawn and hence I connected an ammeter in series with the 5V line and am measuring the current. I ...
1
vote
3answers
101 views
How is current lowered as Voltage is increased in AC power transmission
I was reading about power transmission on wikipedia and came across the explanation of the efficiency of AC power transmission that said power in the load = (I^2)* R while power transmitted= IV. The ...
1
vote
3answers
315 views
Modifying an automotive 12V power outlet to disable power when car is off?
Recently, on a business trip, I had a rental car. Now, in my car, all of my 12V power outlets are always on. On the rental car, some of them were always on, some of them were only on when the car was ...
1
vote
1answer
121 views
Arduino Nano: This schematic would work?
If I used this 9v battery, and a 6v battery pack(AA battery), would this combination work.
I want to it run disconnected from the PC.
Sorry my bad english.
3
votes
2answers
84 views
Power switch for a dive computer
I am creating an open source dive computer (www.diydivecomputer.com) and I am having a little bit of a problem trying to figure out how to power the device on and off. The problem is that the device ...
4
votes
1answer
72 views
2 full bridge with 2 secondary winding in series… is it possible?
simulate this circuit – Schematic created using CircuitLab
Is this possible? Think of the center tap transformer as a 2 winding connected in series
2
votes
1answer
146 views
Mixing AC and DC power in a circuit
This is likely a noob question, apologies if the answer is obvious.
I'm trying to control a furnace using a 3.3V microcontroller. The furnace operates by connecting a common 21V AC "hot" line to one ...
2
votes
2answers
121 views
Power Electronics for 3.3v or lower MSP430 + 10v sensor
After asking around I realized that switching regulators should be used to regulate the power going to the MSP430. I'm wondering (I'm not very informed in the topic of power electronics) how can I ...
3
votes
2answers
140 views
How can I break one circuit when another one's current draw is high?
A layperson here. I own a small RV park, as well has a nice large Motor Home. Most of my guests have the same set up in their Motor Homes as I do. The Microwave and the Hot Water Heater are on a ...
49
votes
6answers
11k views
What is the difference between Vcc, Vdd, Vee, Vss
I've seen lots of schematics use \$V_{CC}\$ and \$V_{DD}\$ interchangeably.
I know \$V_{CC}\$ and \$V_{DD}\$ are for positive voltage, and \$V_{SS}\$ and \$V_{EE}\$ are for ground, but what is the ...
1
vote
1answer
64 views
What are the application difference of the circuit breakers which have difference “Circuit Breaker Characteristic Trip Curves”
I know the difference of different type of "Circuit Breaker Characteristic Trip Curves". However, I don't know what are the application difference. Please help
2
votes
3answers
82 views
Find current and power factor in circuit
This is a picture of a homework question that I do not understand all too well. The question is below:
The power supply in Fig. P9.59 generates 50 kW
the line impedance is 0.095 . If the load ...
6
votes
8answers
344 views
Isn't current flow a wrong term?
In most text books and other electronics material it's said current is flowing through the circuit. Isn't this wrong? As current is flow of charge. Is there anything such as flow of flow of charge?
5
votes
1answer
435 views
How do they calculate the output power?
I'm building a quadcopter using Cortex A8 and I would like to use this USB WIFI dongle.
According to the description this is 3000 mW. What does this mean? 3000 mW consumption? In the USB 2.0 the ...
1
vote
1answer
47 views
Values in a solar array
My dad had just bought a solar array of 4kW together with an inverter, a kaco powador 4400.
The array is now running and generating electricity. I am trying to understand how it all works, but ...
5
votes
1answer
69 views
Powering sub-sytems on a robot with a single battery
I am making a robot for a project, and have a quick question about the power system for my robot. I have to power an AVR MCU (5V), 6 servos (also 5V), 4 dc motors (12V), and a camera (9V). I really ...
-1
votes
2answers
114 views
Is it possible to amplify a sine voltage by a factor of 190? [closed]
I would like to amplify a sinusoidal wave (-1.23V to +1.23V) to a wave between -230V and +230V.
I am planning to use a 12V@8.1Ah battery as my Vcc source.
My question, Is this idea possible? If it ...
2
votes
2answers
135 views
DC-DC Converter Power Supply
I'm looking to build a motor controller where I want to have consistent motor performance. Normally you have a 6v DC motor and you can plugin a 7.2v battery pack directly and be fine, but the motors ...
2
votes
2answers
114 views
100-240VAC 0.25A to 24VDC 0.4A Swiching Power Supply AC Ground
I'm working on a low-voltage power supply and relay design. The switching power supply, a Mean Well PM-10-24, works on 100-240VAC, 0.25-0.15A 50/60 Hz and outputs 24VDC 0.42A. The AC inputs are AC/L ...
-4
votes
3answers
92 views
DC supply voltage divider [closed]
I want to divide a 25volt DC supply to 12 and 12 volt DC.
Is there any way to do this?
3
votes
2answers
128 views
Is it OK to have data lines and AC in the same multicore cable?
I need to provide the following over sections of 1m multicore cable, totaling around 15m.
240v AC
5v DC
GND
RX
TX
Will the AC cause problems for the Serial data?
1
vote
2answers
73 views
74 Series Logic Power switching with Gnd? (74Hc86)
I'm trying to cut power to the chip to "disable" all outputs without needing to know the input values or changing them. What happens if I use a NPN transistor to let the GND pin float and pull it to ...
-4
votes
2answers
127 views
AC to DC power supply [closed]
I am trying to make an AC to DC supply to run my motors,
motors needs 12 to 24 volt and 1.6 amp current.
So i used a transformer(output 12 volt, current 1.5-1.8 amp) ,then a full wave bridge ...
0
votes
1answer
38 views
Considering Loading in analysis and design
What are the conditions under which loading can or cannot be ignored? I would like to be able to design a circuit in segments and then connect these segments together to create a circuit that performs ...
-4
votes
1answer
49 views
On Electro-galvanic fuel cell [closed]
Hello for every one ,
my close friend is going to design some of Electro-galvanic fuel cells , and he seeks for more information about it ,
how does it work ?
what are the laws of physics which ...
3
votes
1answer
99 views
Kilowatt Hour Definition
This is a very simple question but something that I'm not able to wrap my head around. This Energy report states generated electricity. But what does "generated killowatthours" mean? I know that ...
1
vote
1answer
62 views
Upgrade cheap power supply
I want to power my project(AVR uC + RF transceiver) with a fake iPhone charger whose internal is the same as this one, but with a smaller input and output capacitor. I therefore suspect that the ...
1
vote
1answer
83 views
Wingman Wheel with different power supply? [closed]
I have an old Wingman Formula Force running on 20V / 1.5A, and I've lost my original cord/power supply.
I have 2 other supples in here, one with 12V / 2.5A
Second is 22V / 1230mA (guessing that's the ...
1
vote
2answers
115 views
Choice of 5V connector for power
For a small project I'm working on, I am trying to decide the best route to take for the power connection to the device. It will be running on 5V and, in its current iteration, draws less than 100mA ...
6
votes
3answers
1k views
How to calculate Real Power and Power Factor using an Oscilloscope?
I'm trying to calculate the Real Power consumption of my device in Stand-by mode, but to do that I need to figure out its power factor due to:
Real Power = Vrms x Irms x PF
Now, my device like many ...
0
votes
0answers
47 views
Power management/collision with USB OTG [closed]
I've recently got a device (actually - Samsung Galaxy SII) with USB OTG capability and am curious how does it resolve power conflict.
If the device is plugged to power supply or computer, it charges ...
1
vote
3answers
610 views
Using ATX PSU as stand-alone power supply: PSU doesn't stay on longer than ~1 second
as the title suggests I am trying to use an ATX power supply (Seasonic modular X-1050) as a stand-alone power supply. I have roughly followed guides available online, the best of which I have found to ...
0
votes
3answers
167 views
How to control 0 to 110 of AC with microntroller rms output of 0 to 5 v
Is it possible to control high current with small rms voltage?
UPDATE
Do you think that this is gonna work?
-4
votes
1answer
60 views
how do i power my LEDs [closed]
I am currently working on a display board for my church. It contains a static LED display built with light chaser technique and a moving dot matrix display. I am through with the last two but to ...
2
votes
1answer
206 views
Designing a PI controller for my power system
I have a power system which is given as:
Using MATLAB, I found the system's response to be:
As you can see, the system is not stable. So, I need to design a PI controller, so that, the transient ...
1
vote
1answer
81 views
Powering the output side of a voltage regulator?
Would powering the output side of a voltage regulator cause any damage to it? (The ground pin would be attached as well) It will not be normally, but I am making a multi-voltage power converter and ...
7
votes
2answers
197 views
Grounding and why charge leakage occurs
A basic nugget of info is missing in my end-to-end picture of how grounding works and why it's important. When a voltage is applied in a circuit the electric current starts flowing (or the field ...
2
votes
2answers
100 views
Mains on a single core wire?
I have some single core wires normally used in simple breadboard circuits to handle 5V.
I have built a power supply circuit on a perfboard, with a standard transformer + capacitor + 7805 build. Can ...
0
votes
0answers
86 views
ULN2003a and Relays
Hi! We need help for this problem.
This system is about switching relays. We are using one 6V relay for the six loads for the light breaker 1 and light breaker 2.
The light breaker 1 relay and ...
0
votes
3answers
153 views
Lower Voltage of 15 VDC Power Supply to 13 VDC for DC Blower
I have a centrifugal blower, model 007-A42-32D, that uses 12 VDC at 17.5 amps. The performance information provided by the manufacturer, SPAL Automotive, was acquired at 13 VDC.
I have a power supply ...
3
votes
1answer
137 views
Why does this insulator separate two conductors with equal voltages?
Here goes a view-from-below picture of a 3 kilovolts DC railway catenary
Here B is a suspension cable, C is a two-stranded contact wire - one which the train pantograph touches. Between B and C ...
1
vote
2answers
94 views
Question about using N-channel MOSFETs in a current sharing controller
My question is specifically regarding LTC4353 :
Product link: http://www.linear.com/product/LTC4353
Datasheet link: http://www.linear.com/docs/41582
Looking at the diagram on the product ...
1
vote
1answer
86 views
What's the input resistance of an opto-isolator?
I need to sense if a 48 volt power supply is supplying voltage or not, I plan on doing this with a opto-isolator and I am happy with the output circuit from isolator.
Can I connect the input of the ...
1
vote
1answer
97 views
powering a fan with ATX PSU 5v standby when off, with 12v when on
Using an ATX PSU, how would I design a circuit to power a load (dc fan) with 5v standby when PSU is off, and with 12v when PSU is on. I want to control (on/off or pwm, it should not matter?) the fan ...
3
votes
3answers
121 views
How can I switch a high current with a low-rated switch?
I'm designing and building a breadboard power supply for myself, which draws power from an ATX-like SMPS (Mains in, single Molex plug out) via a 4-pin Molex connector. The design includes a switch to ...
5
votes
1answer
131 views
Any disadvantages to single-supply mode?
I am using the ATMEL ARM SAM4S MCU for a project. It supports a single-supply mode where an internal voltage regulator provides the 1.08-1.32V necessary for VDDCORE and we need only provide 1.62-3.6V ...
-6
votes
2answers
149 views
Battery with most mAh that outputs between 1 and 1.5v? [closed]
I am looking for a rechargeable battery between 1 and 1.5 volts that can provide this voltage for the longest amount of time (most mAh). Any suggestions? Thanks.
4
votes
2answers
157 views
Creating a high-current bus on a PCB
I'm planning a custom power-distribution / fuse-board for in-car application, but that requires carrying high currents (50A+ @12v*) on a PCB trace. Since I'd like to keep the board cost, and physical ...
0
votes
0answers
87 views
Design of an inverter required to run 5 laptops and 1 LCD (32") for 8 hours
I need to design an inverter which will run 5 laptops and one 32" LCD screen for 8 hours.
As per my calculation,
average laptop = 135watts
average LCD = 82watts
wattage for 5 laptops = 135*5 = ...
5
votes
4answers
200 views
Measuring total energy used by a project
Is there a cheap/simple way I can empirically measure the total energy used by my project over a sample time of several minutes?
It's a microcontroller based system which repeatedly wakes up, does ...
