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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1answer
53 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? [on hold]
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 ...
0
votes
0answers
31 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 ...
1
vote
2answers
83 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
vote
1answer
58 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 ...
1
vote
3answers
68 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
votes
5answers
230 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
79 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 ...
0
votes
0answers
11 views
Pre-Romex AC circuits to DC for offgrid Solar [migrated]
We live in a rural 250 year old colonial that was wired for ceiling and wall sconce electric lights sometime in the mid-1940s. In the early 70's outlets were added, then updated to Romex when a ...
0
votes
2answers
61 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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votes
0answers
42 views
need help for building a 12 volt dc generator (actually a self running generator). please have a look [duplicate]
i am form india and i need help to build a 12 volt generator which is part of my project. i am in 12th class(grade12). basically it is project , but for me it is more than that. i rule my school in ...
1
vote
1answer
33 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
97 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 ...
10
votes
3answers
731 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
votes
3answers
66 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 ...
0
votes
0answers
52 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
60 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
votes
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
0answers
17 views
How to drive 5 cd motors with one motorshield [migrated]
I have the adafruit motorshield which contains 4h bridges and is therefore capable of driving 4 dc motors. I want to add the capability of drving one additional motor (it does not need to be activated ...
0
votes
1answer
69 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
314 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
vote
3answers
70 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
75 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
vote
3answers
86 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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votes
2answers
76 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 ...
1
vote
1answer
60 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 ...
0
votes
2answers
61 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
votes
2answers
95 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
382 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 ...
0
votes
2answers
109 views
LED supply from 230V AC
How many LEDs can I supply from my home power supply.
If I make AC to DC the voltage drops too low.I read this article but dont tell the output DC voltage http://www.wikihow.com/Convert-AC-to-DC .
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votes
1answer
75 views
Converting 15AC to 5VDC [closed]
I'm currently working on my project that teacher gave.I need to convert my 15VAC input to 5VDC output.
EDIT : I am so sorry. I am not experienced user. I should give you more information about where ...
2
votes
2answers
73 views
Replacing a battery pack with a mismatched DC source
I have a PCB which is nominally powered by a custom battery pack. Specifically, this battery pack:
So five cells connected in series, at 3.6V each, which I assume means that the nominal output ...
2
votes
2answers
222 views
DC Motor as DC Generator + Output Polarity Switcher
I am working on a hobby circuit. And got a quick question.
I am using regular mini DC Motor as DC Generator. If the motor is rotated one side it generates few volts.
If the motor is rotated in ...
0
votes
2answers
50 views
How can I tell if my current is continuous in a first order DC circuit with a switch
Assuming this circuit has been running for a long time (switch SW1 is closed), and in t=0 the switch (SW1) opens, and I'm being asked about the current that runs through the inductor L1.
I know that ...
0
votes
2answers
89 views
Protections against spikes in the design of AC and DC electronics?
Assuming that you are focusing on the choice that will give the best protection against spikes, would you go for an AC or a DC powered piece of electronics? Could you explain why and if this is your ...
3
votes
4answers
401 views
Voltage Divider DC 1000W for LED
I´ve done some research but not clear solutions are given to this problem, so I will post my case here in case somebody can help. Thanks in advance.
I want to use a DC power supply to power up 121 ...
1
vote
2answers
94 views
The math and the physics behind POTS phone lines
Since high school you learn something about Fourier Analysis and you can easily grasp the idea that a given signal that is variable over a given timeframe, is composed of multiple sub-signals with ...
1
vote
0answers
67 views
Removing DC bias current from PWM driven transformer
Previously I asked this question about circuit topologies for driving a transformer by a PWM signal. From the answers and comments under that question, I understood that the DC bias current is ...
3
votes
2answers
277 views
Diode circuit analysis using ideal diodes exam problem
I've been reviewing some past exam and stumbled across this question
So I need to find the current I through the middle diode and the voltage across the bottom left 10KΩ resistor.
To try solve this ...
0
votes
1answer
87 views
Adding Speed Control for a DC Motor
Relatively new to circuits, but I have found this good motor control circuit for a DC motor (I have 2 microswitches, each one reversing the direction of the motor), the only thing is I am having some ...
6
votes
4answers
523 views
Trouble finding Thévenin equivalent for this circuit
I'm having trouble finding the thevenin equivalent for this circuit
To solve this problem, I changed the voltages from 20V and 5V to 25V and 0V as shown below
My resulting output voltage is 10V ...
0
votes
3answers
154 views
Can I power a 5V USB hub using 5.33V DC or should I use 7V with a 7805 voltage regulator?
I'm basically loading up enough batteries to run a USB hub and a webcam. The USB hub is rated at 5 volts. Right now I've connected 8 batteries (these batteries, if relevant)
in series and in parallel ...
0
votes
0answers
34 views
Can a device requiring a 18v 2a DC wallwart, take a charge from my spare 19v 2a DC charger? [duplicate]
Can a device requiring a 18v 2a DC wallwart, take a charge from my spare 19v 2a DC charger? Just worried about that extra volt. Is it significant enough to damage the device or will I be fine?
0
votes
2answers
90 views
Does 1Vac matters to a Arduino pin?
I am planning to do a current measurement with Arduino. The board I'm using is mega 2650, operating voltage is 5V (I/O pin limit is 3.3V). And the CT I'm using is exactly the same as this tutorial, ...
0
votes
1answer
45 views
What is the difference between these two relays?
1- DC12V Coil Power Relay 10A DPDT LY2NJ HH62P HHC68A-2Z With Socket Base
2- Amico 12V DC Coil Power Relay DPDT LY2NJ HH62P-L JQX-13F 10A With PTF08A Socket Base
First assumption is that they are ...
3
votes
4answers
463 views
How can I reduce voltage from 40VDC to 5VDC?
I'm working to power a micro controller that requires something like a USB power supply - 5VDC with a normal draw of .75 - 1 amp but could possibly draw as much as 1.5 amps.
I know that with smaller ...
0
votes
1answer
75 views
Identifying DC electrical power connector
I have here a PowerFilm 10 Watt F15-600 Solar Panel, and attached to the panel is this connector:
The male end attached to the panel has a little green rubber gasket on it and the female end ...
0
votes
1answer
24 views
Simple sound pulse (or frequency) to voltage for switch
I am building a tiny project using an android phone -- it simply has to drive a transistor switch on and off. Instead of going down the route of trying to interface to a micro controller via ...
5
votes
2answers
381 views
DC bias difference between square and sine wave?
I have a 90V DC voltage, VPP.
I have a 10Vpp (-5V to 5V), 100 kHz square wave that I'd like to re-bias at VPP/2.
Here is the output from LTSpice:
Biased output starts at 45V and then 10V is added, ...
1
vote
1answer
55 views
Should the Gauge of wire be consistent for DC
I'm looking at an ATX Power Supply with 2 rails each with a specification of 12 volts @ 20 Amps. That should be a maximum of 240 watts (per rail). The modular plugs/cables that plug into the power ...
