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
155 views
AC / DC Backup Power Supply For Solar Irrigation Pump
I think this technology exists but I don't know what the device is that I need to do the job.
I need a DC Power supply that will pull input 110V - 220V AC (for here or international) and will output ...
0
votes
1answer
265 views
What's the best method for generating 5V at 2A?
I'm trying to make a crank DC charger. I understand the voltage regulation circuitry and (if needed) the bridge rectifier circuitry, but I'm still a total noob. I'm wondering what is the ...
2
votes
1answer
575 views
Voltage, Ampere and and Ohm of a DC motor
This might be a quite simple question. I have a small DC motor (it seems to be this one). This webpage suggests that it needs 6V. I have a power supply which outputs 6V and writes "0.6A". But when I ...
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2answers
494 views
Connecting 5 12V LEDs in a parallel circuit
I recently bought 5 12V ultra bright LEDs (all identical), and want to hook them up to a battery pack of 8 AA batteries. So I figured I could just make five parallel circuits with one LED in each, and ...
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1answer
180 views
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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3answers
78 views
Close a circuit at specific input frequency
I have several very simple circuits comprising of a battery connected to a LED. Additionally I have an input signal at some frequency, which I need to use in order to control these circuits. What I ...
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9answers
18k views
How does a capacitor block DC?
I am confused with this! How does a capacitor block DC?
I have seen many circuits using capacitors powered by a DC supply. So, if capacitor blocks DC, why should it be used in such circuits?
Also, ...
3
votes
2answers
127 views
Do I need to double the voltage with double the motors?
I am totally new to electronics.
Let's say I am building a DC circuit with a motor using 6V taking 1.28A.
Now, if I build a circuit that uses two of these motors, will I power the circuit with 6V and ...
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4answers
3k views
How to increase current of a DC circuit
Well.I am new to electronics. I have just started creating small circuits. Coming to the point,I have a circuit with 5v input and current in the circuit is 2ma but I have a requirement to increase ...
0
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1answer
138 views
going from 5volt 1A to equivalent from a 3V CR2 Battery
I have a small camera with wifi that runs off a 3V CR2 battery. I'm trying to run it from line voltage. Could not find any small transformers that go to 3volt 750mA.
I have an Apple transformer for ...
3
votes
3answers
634 views
Is Frequency for dc is zero?
We know the frequency of a direct current is zero. The reason is that there is no repetitive pattern.
But i was stumbled when i notice, why cant that straight line be cut into smaller pieces, and ...
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0answers
86 views
RMS to DC Conversion
Do you have any suggestions of a chip / circuit I could use to get the RMS (or MAX) value of a 40 MHz input AC signal?
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2answers
205 views
Need to automatically switch a 12v 1amp dc pulse between 2 alternating outputs
I have a control unit that produces two 12v 1amp dc pulses lasting about 200ms.
There is a gap of about 100ms between the pulses
I need to automatically switch these pulses between 2 outputs ...
3
votes
2answers
6k views
230V AC to 5V DC converter, lossless
Is there any IC which converts 230V AC to 5V DC? As lossless as possible. I want to connect my microcontroller to an ordinary electrical socket and I don't have enough space available. Thanks.
3
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1answer
121 views
Identifying an irreducible circuit?
How would you go about identifying an irreducible circuit? By irreducible, I mean combining resistors whether in series or in parallel to reduce the circuit.
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1answer
183 views
diode nightmares
Let me start by saying I am a complete amateur trying to stumble my way through some pretty basic PCB design, and I have run into a problem selecting diodes. The PCB I am designing will be for some ...
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1answer
531 views
Advice for building a dual rail, +- 10V, regulated, DC power supply, 25mA
I am looking for some directive to build a dual rail, +-10V, regulated DC power supply to supply 25mA to two resistive loads. I am very new with this; I am an engineering student and this is my first ...
4
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1answer
2k views
what will happen if i apply 220 dc voltage to 220 ac system (load) like lamp?
Please help me. Let say if I have a lamp which is operated on 220 V ac. Instead of applying 220 AC voltage I apply 220 DC voltage then what will happen? And if i want to convert this 220V dc to 220V ...
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3answers
177 views
Beginner Kirchoff Voltage Law in DC circuit
Why is the voltage \$ V_A = 2.5V \$ in this circuit?
I know the current in the mesh by applying KVL is:
\$ I = 50 \mu A \$
but why is
\$ V_A = \dfrac{V_1}{2} + \dfrac{V_2}{2}\$?
How do the ...
2
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1answer
434 views
Amplifying signal from CO2 Sensor
I am trying to amplify a MG811 CO2 sensor to a range readable by an ATMEGA2560 (0-5v). I have other analog sensors, so do not want to change ref voltage on Atmega. I have found a module that scales ...
4
votes
1answer
326 views
How should I isolate AC and DC on a small PCB?
I am designing a small PCB (1"x1") and it will have some DC logic traces (5V and GND) and some high frequency AC power traces (100V 1000Hz 50mA). Are there any special considerations I need to take ...
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1answer
178 views
3V triggered switch using an IC
I have, what I'm sure, is an absurdly simple question:
How do I step up 3 volts to 5 volts using either an OP_Amp or an XOR IC?
Background:
I have a 5volt power supply.
I have a 3volt output from ...
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1answer
178 views
DIY 2.5mm DC power splitter? [closed]
I'm looking for one of these DC power splitters: http://www.amazon.com/5-5mm-Double-Power-Supply-Splitter/dp/B0050H9A18
but for 2.5mm instead of 2.1mm.
I'll be using it to connect two external hard ...
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votes
3answers
377 views
L7805CV 5V Voltage Regulator 1.5A
I seem to be having some problems with hooking up the L7805CV Regulator. When i provide it 12v @2A i seem to be getting an output value of 10.xxV???
What could i be doing incorrectly? Does it matter ...
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1answer
239 views
Why use a resistor when blocking DC?
This may be a silly question, but I was wondering about the resistor involvement of a DC blocking network employed at frequencies 5MHz to 2400MHz.
Most of the designs I have seen are an RC ...
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3answers
164 views
A device that runs on AC current it's voltage inside is measured by always turning the multimeter's knob to AC voltage:same for DC right?
I've bought a cheap multimeter and it's not automatic. I've to manually rotate the knob.
I live in North America. AC current is used in my home. Does this mean I can always measure voltage by turning ...
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3answers
720 views
Correct DC Adapter type to use for Arduino
What's the correct DC Adapter to use with Arduino? Voltage etc?
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1answer
176 views
Solenoid Power Source
So Im trying to make a solenoid a switch, but I have heard two different ways to power it: AC or DC power source. I learned in class that an AC power source would work because a solenoid is basically ...
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0answers
66 views
Choice of an electric motor for a motorcycle [closed]
I'm new here and this seems to be the suitable place to ask for help(correct me if I am wrong).
I am planning on building a motorcycle powered by an electric motor, but I am facing a big problem : I ...
5
votes
1answer
966 views
Current measurement with a multimeter: how am I doing it wrong?
I want to measure the current draw of a strip of LEDs. This depends on the intensity of the pattern the strips are running so I need to do it in "real time" to get an accurate idea, rather than just ...
3
votes
1answer
182 views
DC motor vs AC motor weight considerations
For a given power rating, does a permanent magnet DC motor have a weight advantage over either a three phase permanent magnet synchronous machine, or vice versa? Or does it work out that they would be ...
2
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1answer
159 views
DC power supply and cell phones
I just purchased a Gordak Instruments DC Power Supply PS-3005D for getting a power to cell phones that we do not have the battery for. Could someone let me know how to set the correct voltage output ...
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0answers
190 views
Help with using mosfets to switch positive and negative supplies
Can any one please direct me to a schematic for a MOSFET based DC switching circuit whose output switches between +100V and -100V. I already came up with the MOSFET driver circuits to switch the ...
3
votes
1answer
213 views
Regulate DC-Pump throughput
Does anybody know whether it is possible to easily regulate the throughput of a DC water pump? E.g. one you would use for your pond or indoor fountain.
I would like to avoid lowering the duty cycle ...
2
votes
2answers
112 views
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 ...
2
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2answers
562 views
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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5answers
1k views
acceptable bounds for replacement DC adapter [duplicate]
Possible Duplicate:
Chosing power supply, how to get the voltage and current ratings?
I've got a broken gadget that is discontinued. The only thing broken is the power supply (verified by ...
9
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5answers
2k views
24VAC/5VDC power supply design
I am planning to create a water valve controller using an MCU and a set of solenoid-controlled valves. The solenoids run on 24VAC (40mA inrush, 20mA holding).
The MCU is on a board that draws ~100mA, ...
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3answers
286 views
Use household 12 V DC adapter with RFID transponder?
Is it possible to use a common household 12 volt DC output adapter with this RFID transponder. I am a newbie but I am willing to learn. Here is a diagram of this RFID transponder system of this.
...
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3answers
291 views
How to design for a component that says “Electrical Design: DC PNP” in the datasheet?
I'm not a guy from electrical engineering and I'm having a little trouble with a small garage project that I'm working on.
I want to use a photoelectric sensor to measure distances. I'll probably ...
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votes
3answers
289 views
Voltage Limit of CAT 5 DSL wire
I have been using threads(single wire) inside CAT 5e wire in a project for providing input to the circuit and output to a telephone. The source is 50V DC but the input to my circuit is just 4.86V DC ...
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votes
6answers
3k views
Why is feedback required in op-amp circuits?
I understand that, in order for an op-amp to function correctly, a DC feedback loop from the output to either the inverting or the non-inverting input (depending on the external circuitry) is ...
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3answers
688 views
What happens if usage current exceeds DC adapter current rating?
I have a DC adapter 5 V, 350 mA. I'm using this adapter to be fed into a 3.3 V regulator which powers up my bluetooth device and a few LEDs.
My question is: what happens if I source 300 mA from this ...
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votes
1answer
154 views
What is the difference between a PT3 and a PT4 power lead?
I want to know the difference between a PT4 and a PT3 power lead.
Can I use them interchangeably?
http://www.cctvcamerapros.com/CCTV-Accessory-PT4-p/pt-4.htm
...
0
votes
3answers
251 views
Advanced DC fan controller [closed]
I am wondering if I could get some advice for my final year project. Last year, for my 'mini project' I made a DC fan controller that activated the fan at a specified temperature, to cool it back down ...
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votes
3answers
512 views
Can the Arduino (or other electronics protoyping boards) deliver direct current waveforms for muscle and nerve stimulation applications?
I am currently interested in Transcranial Direct Current Stimulation (tDCS), and I have observed that most studies in the field utilize DC-Stimulation equipment from manufacturers like NeuroConn and ...
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2answers
1k views
Easiest / cheapest way to build a dc power supply in the 0 - 50V DC range?
I would like to build a small DC power supply (or find a cheap way) that allows me to get voltages in 0 - 50V DC range.
I had a look on ebay and some electronic shops but most supplies dont get ...
4
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1answer
164 views
Implications of using 145 ohm cable for RS-485
My current workplace has made up some custom cables that have conductors for DC power and conductors for for RS-485 communications in the same bundle. My predecessor apparently had the cables ...
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2answers
2k views
How do the tiny AC->USB power supplies work?
The iPhone and Kindle both come with tiny power supplies that take in 120v AC and output around 5V at 0.85 to 1 amp. They seem to be too small and light to have a transformer, and generate very little ...
5
votes
3answers
842 views
How does DC transmission require several times less wire than AC?
In this YouTube video (scrolled to 5:55) there's a claim that replacing an AC high voltage transmission line with a high voltage DC transmission line allows for having seven times fewer powerlines ...
