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, dynamos.

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AC voltage gets mixed with DC

I am using ATS (automatic start) for my generator. Its programmable IC goes out of work after 2 or 3 days and I have replaced 3 ATS card. My card supplier says that you are somehow getting AC voltage ...
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2answers
43 views

How to select most efficient motor for generator?

First post. Please forgive me if this is a stupid question. This post can be broken down into two questions. I am building a bicycle generator, but am new to the field of EE. I am trying to select ...
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2answers
97 views

Amplify DC Voltage to be used like supply to 2Km

Is there something to help me to reach this goal? I want to turn on a device away from the voltage source to 2 Kilometers, my device operates at 24VDC or 48VDC / 35W. I need to know how is possible ...
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0answers
49 views

My personal battle in repairing my Asus Zenbook's DC in [on hold]

I'm struggling here saving my laptop. Zenbook's charger gives problems to lots of people google says, and it was giving me problems too. I tried buying a new one, but it ended up not working well ...
0
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1answer
44 views

Good volts and amps but phone still charging slowly

I am really new to the EE game and am still tinkering. I have built my own portable DC power source similar to a Minty Boost from scratch and plugged it into the USB port of my Galaxy S3 and it ...
2
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2answers
86 views

Circuit to pass voltages above a threshold level

I have a sine wave signal centered around 2.5 volts (1/2 Vcc) in which I require the the upper half only, brought down to 0 volts, so a 2 volt peak-to-peak input around 2.5V would become a half sine ...
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0answers
69 views

SEPIC hardware problem [closed]

I am doing my project on SEPIC converter. It seems that the switching action between drain to source is happening only at low voltage. At high voltage it does not work. What seems to be the problem? ...
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0answers
6 views

Wiring Relay & Horn on Golf Cart [migrated]

I've had this wired up in the past but I forget how it was done and some things came apart. We have a simple 12v horn and relay. The relay is a KUMP 7D58-12. Here (http://imgur.com/a/dtBFo) are some ...
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1answer
31 views

Can the volts and\or amps in a repalcement DC power cord vary without problems? [duplicate]

In general I've always wondered about this but now I have lost the DC power cord to my portable speakers. The manufacture does not have a replacement or at least one I can find. The specs are 12.5 V ...
0
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1answer
48 views

24v 450w DC motor powered electric bike connected to a lith-ion battery pack (56v 6.5a)

How do I prevent the DC motor from burning out using this battery pack?
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2answers
91 views

What wattage solar panel required for AC 1000 watts

If my house load is 1000 Watts AC/220V, then 1000 Watts DC/12V solar panels is not enough. What wattage solar panel would be required for AC 1000 watts?
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3answers
459 views

How many Watts DC are equivalent to 1,000 Watts AC? [duplicate]

How many Watts DC are equivalent to 1,000 Watts AC? For instance, my load in AC is 1,000 Watts 220V. Then, how much DC watts would an equivalent load dissipate in 12V or 24V DC system?
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2answers
29 views

Control automotive AC switch via TPS voltage

The A/C compressor is engaged via a single wire that comes from the 'A/C' button on the dash board. I want the A/C button to disengage when the throttle is at 50%. The throttle position sensor (TPS) ...
0
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3answers
148 views

Grounding a capacitor?

Noobish question. I'm trying to make a dc variable voltage power supply. I will include the schematic which I am trying to build. In the schematic there are two 1000 uf capacitors which I believe are ...
0
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3answers
70 views

Diode in parallel with two DC sources

Please help me to find the answer for the following question from Flyod 9th Ed. Determine the voltage across the diode in the following figure, using the complete diode model with r'd = 10 Ohms and ...
1
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1answer
48 views

How do I replace an existing servo with a geared DC motor?

I am a complete beginner, just getting into the world of electronics, in particular robotics. I have found a really nice open source set up that I want to build on and change for my own ends. The ...
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4answers
134 views

How to drop 240V DC to 5V DC

I would like to drop a 240V DC voltage to a 5V DC voltage to supply electronic. The 5V stage needs less than 5mA in current. The solutions I looked at are: Resistor divider (Not really ...
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0answers
40 views

How can I use a 9v chaser board to run LED strips

a few years ago I bought an LED sequencer circuit board kit. Once assembled you can adjust the pace and the brightness with 2 POTs of up to (I think) 8 LEDs. this board runs off of a 9v battery and ...
0
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1answer
77 views

3V and 5V supply Topology (Embedded Design, Mixed Signal)

I am developing a mixed-signal embedded system that requires both 5V and 3V rails. The 5V rail powers an analogue sensor and a precision ADC. The nature of the sensor is such that its output will be ...
0
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1answer
31 views

Varistor over clamping voltage at DC

First of all, I know I should not use a varistor at a DC level higher than its clamping voltage, but I want to do it for a test (destructive or not). What I want to know is what is the maximum current ...
1
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6answers
168 views

Why do cables and batteries have a positive and a negative side?

I am a beginner in electronics, mostly self-taught. If electrons are negatively charged and are the reason for electric current why is there a 'positive' side on a battery and negative one? Don't ...
2
votes
1answer
85 views

DC current stopper [closed]

I don't really know what I am looking to make is called so I am going to try to explain it. I set up a motion activated light in my room. The lowest time interval is 60 seconds and I am okay with ...
0
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1answer
44 views

DC motor spun clockwise then counter clockwise creates AC current?

I am making a generator with a DC motor but the style of turning the rotor would be clockwise and then counter-clockwise, and I would want to capture as much current as possible so I hope it could be ...
0
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1answer
52 views

Battery pack for DSLR coupler

I am planning to make a battery pack, by using rechargable batteries, that i can use to power my DC-coupler for my DSLR camera. (Ref. Image) On my original camera battery it says 7.4V 1.2A but i ...
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votes
1answer
57 views

VHF radio - Motorola GM340 - could I have damaged it with too much current? Why would it not be damaged by being connected to a 12v battery? [closed]

I connected a Motorola GM340 VHF radio to the 12v DC converter for another radio, an ICOM IC78, which gives 13.7v at 16 amps. The wiring did not have a fuse. As it did not work, I wonder if the ...
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0answers
34 views

LED bulb that works on both 64 volt DC and 110 AC

Can anyone advise on a reliable/cost-effective way to modify a screw-in LED light bulb so it will run on an AC power supply that has a battery backup where DC is provided in backup mode (this is for ...
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2answers
93 views

6V DC Motor Overheat

I am totally new to electronics, so be patient with me please, it is very basic question :) I have a 6V DC motor which I reused from an old device, that means I don't know its specs. I connected it ...
1
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1answer
64 views

How can I create a DC-DC voltage multiplier [duplicate]

I want to take the 5V output from a USB port and make it 12V, so that I can run a cooling fan which is 12V. Is there any circuit I can make at home myself? If the output voltage is not exactly 12V, it ...
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3answers
77 views

Stable power for LED from 5.5 to 7.5V AC

About a year ago I posed the question "Making 12V DC from 6V AC". Since the conversion from AC was going to be problematic (for me), I tackled the tail/brake light first, because working with the 6V ...
3
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5answers
278 views

Why do electronic circuits need their power supply to be DC, or rectified AC?

I'm pretty sure the answer to this should be obvious - even to me ... It's been a while I've been reading and attempting to construct simple electronic circuits. The supply almost always is either ...
0
votes
1answer
81 views

How to implement grounding into this electrical circuit?

I'm trying to make some tutorials but I have no idea what should I do when I see the term ground (GND). Here is an example: I want to know how I build the GND part. Where I connect it? Also, if ...
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2answers
69 views

How to protect bistable latching 2 coil relay with diodes?

I know that a revers diode is required to protect a DC coil relay. But to protect this relay RT314F05? It has 2 coils, are 2 diodes enough?
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1answer
39 views

Supernode question

I have run into a question while revising for my exam that I can't seem to wrap my head around. I know I have to use a super-node. Which I have circled on he next image. I don't understand why ...
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votes
1answer
100 views

Transmitting 12v DC over a long wire

I'm trying to charge my laptop through a 12V battery and 12-19V adapter over a long wire but I've noticed that the adapter makes some noise and doesn't work. On the other hand when I connect it close ...
11
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3answers
747 views

What is the difference between a 30 V power supply and a ±15 V power supply?

I need to get a ±15 V power supply and I am wondering where to find it. Should I get a 30V DC power supply in its place?
2
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3answers
74 views

DC power through a female socket

I have a solar panel and I would like to use an extension cord. I know this works (heavy duty extension cord) but the guy cut the ends off of the cord to just use the wire (see video links below). I ...
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0answers
67 views

DC Voltage of a 12V AC transformer after rectification

I want to drive relays using Method 2 of the following question: What is the most economical way to drive an array of single coil latching relays? This basically means that any time the relay is ...
1
vote
1answer
64 views

Is it possible to power an AC-to-DC switching adapter with a DC input?

Typical "wall-wart" switching power adapters are often rated for ~110-240V 50-60Hz AC input and output low-voltage DC. For this question let's assume the output voltage is 5V DC. Internally, the ...
0
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0answers
47 views

Drawing 2A from 1.5A source. What are the risks? [duplicate]

I have 220V to 12V converter with 1.5A output. My simple motor draws 12V and 2A. Are there any potential risks, when the difference is so small (besides motor being slower)? I cant figure out if ...
0
votes
1answer
75 views

Can I damage a device using opposite polarity? [closed]

I have a device that requires input of 12V DC with positive polarity and a power supply that outputs 12V DC negative polarity (see figures below). Can I plug it in to try to see if it's working or ...
6
votes
2answers
330 views

Supply three different voltages from the same pack of NiMH rechargeable batteries

I have a battery pack that I would like to use as a source for all of my battery powered components on a commuting bicycle. My pack includes (10) 1.2V cells wired in series: ...
1
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3answers
83 views

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 ...
0
votes
1answer
97 views

Supply voltage for MOSFET driver in high-voltage (110v) PWM regulator

I am designing PWM speed control for 110v DC motor. Since it is 110v, I am going to power it from bridge rectifier connected to mains, with MOSFET on low side for switching. For driving MOSFET I plan ...
1
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3answers
96 views

DC or (AC + DC) coming out of a full wave rectifier

DC or (AC + DC) coming out of a full wave rectifier Is there a truly correct answer to this? Considering the representation as a waveform I would say its an AC wave form offset by some DC amount. ...
13
votes
7answers
1k views

Why are rectifiers-inverters used to drive AC motors instead of using the rectified current to drive DC motors?

I understand the advantages of using a rectifier-inverter system to drive an AC motor instead of simply plugging it into mains power, as it allows much better control of its speed and performance; but ...
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2answers
98 views

Switching between AC and DC input

Let's say I need to power a 9v device with an input power source that is either AC or DC and changes almost randomly. Is there any way for me to detect in a circuit when AC changes to DC or vice-versa ...
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vote
1answer
62 views

What adapter would power device that runs on 3 D batteries? [closed]

I have a clock that runs on 3 D batteries and, as you can imagine, it's a pain to maintain them. I've found a DC adapter that delivers 4.5v (1.5v x 3) but it doesn't budge when connected. I imagine ...
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2answers
68 views

Raising Alternator Voltage

Does anyone have a good idea on how I could raise the voltage from a 12v car alternator to 48v dc for use in a 48v wind system? Could I put a dc negative voltage of 36v into the regulator field ...
0
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2answers
97 views

Tried connecting 2 things two 1 battery, smoke ensured

I'm assembling a quadcopter and have run into a problem So, I have one two cell LiPo battery if I've understood things right, it outputs about 7.4V and has one ampere hour. Now, I have one radio ...
3
votes
4answers
396 views

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 ...