Questions tagged [dc]
DC stands for Direct Current, which means the flow of electric charge in a single direction. Examples of a DC source are batteries, solar panels, and dynamos.
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Why is 5V DC so common? [duplicate]
I have an arduino, beaglebone black, and an arndale octa board and they all work 5V DC (albeit different amp rates). Most of my electrical sensors seem to operate around the 5V range.
Why is this ...
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Advantages of Isolated DC-DC Converter over non-isolated?
I am trying to understand in what type of situation I will need an isolated DC-DC converter instead of a non-isolated one. What are the design criteria that can lead one to one way or another?
In my ...
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Voltage Divider Supply (Unloaded and Loaded)
The loading down of a system is the process of introducing elements that will draw current from the system. The heavier the current, the greater is the loading effect.
This is the the highlighted ...
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If a wire is rated 10A, 120v AC. How many amps could I put through it of 13.8v DC?
I am using a wire that is rated 10Amps at 120v ACwith a car headlight and a SLA battery. About how many amps could this wire carry before getting warm or melting of DC current at 13.8volts?
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What's this connector pictured called?
Can anyone identify the connector on the right of the picture?
A picture of the same, taken from a different angle:
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Canon no longer makes CanoScan 8800F AC adapters, help needed to replicate its functionality
The CanoScan 8800F uses a proprietary 32VDC AC adapter that's no longer manufactured. A Flickr user did the trial and error to find out how to modify another 32VDC AC adapter for use with the 8800f. ...
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Does electrical current flow from positive to negative or negative to positive?
When you listen to people wiring up a DC circuit they seem to mumble about the electricity flowing from positive to negative. However in school I was always taught that DC electricity flowed from ...
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Finding current using Kirchoff Law, but getting unsolvable system
Hello, the original circuit above is where I am trying to find I1, and I simplify it the figure below and assuming the following current directions.
Using ...
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Can I use a DC SSR that is switched by a PID controller to control the speed of a 12 V DC fan?
This is my first post here. Let me start by saying that I do not have an engineering background. I tinker with electronics in my spare time (Arduino, solid state low-power guitar amps, etc.), but I do ...
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DC/DC Converter minimum load?
I'm using the NTE0506MC DC/DC converter which boosts 5V to 6V. The output voltage I'm measuring with no load is 9V not 6V. In page 3 of the datasheet they mention that it needs a minimum load of 10% ...
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Switching kicker solenoid with an idea out of the box
From my previous posting some may know I am planning to make a kicker solenoid.
The circuit specs:
Coil - 3.5 Ω, 3.4 mH (inductance)
Capacitor 1000 μF, 450 V
DC booster up to 410 V
12 V DC battery
...
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Why to use opto-transistors when controlling a DC motor from a microcontroller?
In the figure(V2 is a DC motor by the way) an isolated way of switching recommended. But what if we use a transistor such as in the figure. Why many say that the motor current would harm the micro ...
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Are there any advantages to either DC barrel connector polarity?
I was putting together a fairly basic LBB at the weekend to control a handful of DC devices which got me thinking. Why are both pin-positive and pin-negative DC barrel connectors used? Are there any ...
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Clean 12v car power
I am looking to get a constant, clean 12V from my cars 12V line. I am wondering if all I am in need of to pull this off would be a simple 12V fixed regulator?
The 12V would be hooked up to a pico ...
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Braking a DC Motor
I've been working on a lab for my electrical class, and I can't quite seem to find the answer.
I have a DC motor that plugs into a 120V supply,from the supply it is connected to the shunt field, then ...
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How do I tell sleeve from sleeve shunt on this connector?
I need to change a DC jack to a different one (with long bushing).
I'm not to sure which terminal connector is what from the manufacturer's diagram.
The DC jack is a L712A from Switchcraft (...
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DC Motor Efficiency at Fixed Torque
I am in a muddle here, so thanks for making the effort to have a read.
I understand that electrical power going into motor is given by:
\$P_e=I^2R\$
I understand that mechanical power out is given ...
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How would I create a voltage doubler and what parts would I need?
I'd like to make a voltage doubler, I've read up on wikipedia and also here. My issue is that I have DC input and I need DC output, first is this even possible, second, if so the problem I'm having, ...
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Using an AC relay for DC switching, safe limits
I have an relay that's rated for a 250VAC, 16A load.
Would it be possible to also use the same relay for say a 25VDC, and less than 1A load?
From here,
relay power ratings - AC vs DC
,
it seems to ...
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Vending machine motor: simple DC motor with microswitch, one revolution
Long story short, I'm currently trying to understand and control a DC motor with connected microswitch, which gives back one-revolution feedback (don't know how). I tried connecting INA219 current ...
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How do I simulate an audio amplifier in Multisim?
I'm new to Multisim and am using the 12.0 PowerPro version. I have designed the circuit in the question TDA2002 Audio Amplifier using Multisim:
The Multisim circuit may be found here. Instead of a ...
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Data over power line in a car
I am trying to build a communications system for a car, for turning gadgets on or off. One idea was to parasite on power lines, but what kind of components and signaling could be used for this? I am ...
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solar panels: multiple roof surfaces on one inverter string?
Notice below part of electric scheme as designed by solar company:
On the left you can see inverter used - Delta Solivia 7.6 TL
(see Operation and Installation Manual for details) which supports up ...
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Supplying ac to a dc circuit
So a while ago, i was stumbled upon a post what will happen to the dc circuit when we supply ac to it. Lets assume the ac has the same voltage as the dc. We know that ac switches direcions so there ...
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Is there a way to miniaturize cell-phone power adapter
Is there a way to miniaturize a cell-phone power adapter to be not bigger than 1-3 cubic centimeters? Is there a way to do so by using more expensive parts or something like that?
I'm talking about ...
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Simple AC line state detection for digital controller input
Last year I moved into a house that has an old ('50s-'70s vintage) GE low voltage lighting control system. It uses 24VAC momentary wall switches to toggle solenoid/latch relays that feed 12 main ...
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Why does this hysteresis curve approach saturation so immediately?
I am trying to find out the hysteresis curve of a transformer iron core. I use an LM741 for the op-amp integrator.
As I increase my 50Hz input voltage, I observe that Vin (value on the x-axis) does ...
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Why do some power adapters output an AC voltage?
Out of most of the electronics I use, I have two, both of them speakers, that use a power adapter that simply steps down the voltage without rectifying it. Why did the designers choose to put the ...
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Does a resistor in an AC circuit produce the same heat as in a DC circuit?
Does a 1k ohm resistor produce the same heat in a AC circuit which has an rms voltage of 10 volts (60 hz.) as it would in a 10 volt DC circuit?
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How can I shift the output voltage of an encoder to an MCU-acceptable voltage range?
I am using an encoder in my circuit operating on 5 V and the maximum output voltage of my optical encoder is 5 V. I am using the TI CC1350 Launchpad MCU to read the encoder signal, but the problem is ...
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Calculate power supply on distance
I need to provide 12V DC to a DC brushless motors that need 12V 30A at distance of 30m from the source.
The cables I can us are 20 Gauge, I know that the cables are loosing power, how can I ...
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(How) can I run a microcontroller and DC motor from the same battery?
I have a microcontroller (a PIC10F200) that I'm using to control a DC motor. It's a very simple circuit. A button is pushed and the pic sends output for certain increments of time. The thought is to ...
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What is the formula for charging a capacitor with constant current?
I read that the formula for calculating the time for a capacitor to charge with constant voltage is 5·τ = 5·(R·C) which is derived from the natural logarithm.
In another book I read that if you ...
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How can you build a floating two-port VCVS?
I have a control voltage at one point in a circuit which I need to duplicate at various other points (3 or 4, if I remember correctly). I'd like to use one potentiometer to control these voltages, so ...
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How to convert 6V AC to 5V DC
I'm looking to convert 6v AC (.5A) to 5v DC for use in charging a phone via USB. idealy a relatively inexpensive pre existing solution would be perfect, but I've been unable to find anything like that ...
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Removing flickering of LED lighting
I am trying to install recessed, dimmable LED lighting in the living room. We're talking about an end solution of maybe 15-20 spot lights. My home has 120V/60Hz.
Currently I am experimenting with a ...
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Assembling and Dis-assembling a Charged Capacitor
If I have an electrolytic capacitor, which is a cylindrical body in which the two plates are rolled-up with a dielectric paper in between them, of very high value (say 1F) and I charge it using a DC ...
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DC Circuit problem, an idea to solve this circuit?
So here is the circuit schematic:
Known values: \$E_6=200V\$, \$E=35V\$, \$R_2=50\Omega\$, \$R_3=100\Omega\$, \$R_4=140\Omega\$, \$R_5=120\Omega\$, \$R_6=100\Omega\$, \$C=10\mu F\$.
When \$P\$ is ...
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Is the resistance in a DC Motor constant if the voltage is?
Is resistance in a DC motor constant if both the load and voltage are constant as well?
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How "slow" is a Class T "slow blow" fuse?
I have a DC inverter that's rated for 3kw sustained with a 6kw peak (for up to 5 seconds).
Per the Inverter manual, the manufacturer recommends a battery fuse rated for "at least 350 amps".
How can ...
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Correct way to do "power injection" from multiple DC supplies?
I'm using a PixLite controller to run a bunch of pixel LED strips. Since I'm sticking to 5V I need to use multiple power supplies (PSUs) to "inject" extra power for the number of LEDs I'm running. ...
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How do you find the voltage across a capacitor at time t= 0 and t = infinity?
Here is a diagram of the circuit, I am confused about problems a and b.
How do I go about solving these two problems? Thanks!
By the way you don't have to tell me the answer, I just want to know ...
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DC restoration of a video signal
I have a composite PAL/NTSC video signal. One problem I am having is getting a reliable sync signal from it; picture brightness causes the sync pulse (normally 0.3V) to vary; so much that my scope won'...
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Why is DC Voltage called Direct Current ?
I have had this question since a long time, and didn't find any other place to ask this. So thought will just ask here.
The "DC" in DC Voltage/Supplies stands for Direct Current. So why is it ...
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When measuring AC via an ADC, is it bad to have common ground?
I've got a circuit that looks like this:
circuit http://img.skitch.com/20111127-m6jqyx9b15brese4rkipayyib6.png
My input is low voltage AC at low current and I want to measure this with an ADC at 3....
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Instantaneous DC output using Laplace transform
I am testing a feedback system in which a feedback signal from sensor is applied to a correction network and then compared with threshold values.
I need some clue on how to get around this task, I ...
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How to tell if brushless DC motor is wired delta or Y?
I have a brushless DC motor I'm working with, do not have any spec. sheets for it. How can I determine if it's wired in delta or Y formation? There is nothing on the label that indicates this. Here'...
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Does the input polarity matter for a 12V DC adapter?
I bought a car cigarette DC adapter yesterday with the following specs:
Input: DC 12V
Output: DC 17V
I'm planning to connect it to a 12V battery I have at home,...
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How does such an USB step-up 5V-12V work? [closed]
I just bought a cheap USB 5V to 12V step up converter:
Surprisingly, it works very well. There is few place for electronic components (maybe in the USB connector?), how can we do a 5V to 12V ...
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Using the same input for AC and DC power
I'm currently exploring a requirement to have a power input to a system which can take both mains AC and DC power. The input would feed the input into a AC/DC converter, or a DC/DC converter, ...
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