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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Led Dinning Table Chandelier construction

I would like to create a brand new chandelier from scratch using G4 1.5w LEDs. I have been searching for the right transformer but I just cannot get started since I need more information about ...
2
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2answers
89 views

+5V and -5V power supply from 12V DC

I'm creating an RGB switcher for a car video system and would like to use the MAX466 chip, which needs -5V, GND and +5V. I have no idea how to change normal 12V DC (car battery) to dual 5V. I found ...
0
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2answers
99 views

Why does the original Nintendo take 9V AC instead of 9V DC?

i have found an old Nintendo NES 9V wall adapter which is in fact not an AC DC adapter because it's an AC AC adapter. It's the first time i see an AC adapter that ouputs alternating current, Why did ...
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1answer
60 views

Can I share the ground between 2 ac adapters with different outputs? [duplicate]

I know there are other ways I can do this, but I'm a little curious about this anyway. Basically, I have a breadboard that's mounted on a typical base that has the typical three posts I can hook ...
0
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2answers
46 views

Does a Breadboard Compatible DC Barrel Jack Have to be Connected to Positive and Ground to Receive Power from an Outlet?

I am using an Arduino to control an electric lock strike but I don't know how to power the lock with sufficient power. To control the lock from the Arduino, I am using a TIP31 transistor (It is NPN). ...
0
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1answer
42 views

Connecting a +12V DC wire to a Voltage Regulator with 4 pinouts

The voltage regulator I'm using has 4 pins (2 in, 2 out) pictured below. The reason I purchased this regulator is that I want to convert +12V DC in to +5V DC current for connecting a Sony Projector ...
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2answers
70 views

Optoisolator not turning off

I'm using an optoisolator for high side switching a Nixie tube. For some reason, the optoisolator is not fully turning off, allowing the a very minimal amount of current to flow through the Nixie ...
0
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1answer
45 views

Fan Control using Motor Driver, looking for suitable solutions

I want to control the speed of a fan (which is a 2-phase brushless DC motor). I am currently using a suitable power supply to run the fans. My source is a Data Acquisition device that outputs up to ...
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0answers
54 views

How can I convert very high, fluctuating, AC voltage to 240VAC at 50Hz?

I'm about to finish a generator-alternator setup which will generate 9-phase AC electricity at (as yet unknown) very high voltage, most likely around 4800V. I'm not sure what the frequency will be, as ...
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0answers
54 views

Laptop doesn't turn on after removing dc power jack from motherboard. Why? [closed]

I had a broken DC power jack that I needed to replace. So I removed it from the motherboard and tried to turn on the laptop with battery inserted to see if it still turned on. It didn't turn on, not ...
0
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1answer
32 views

How Number of commutator segments,air gap between the segments of brush dc motor affect on performance of DC motor..?

plese help me about how Number of commutator segments,air gap between the commutator segments of brush dc motor affect on performance of DC motor..?? now if we we change the number of commutator ...
0
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1answer
74 views

Diode selection [duplicate]

I have a very simple circuit but have no idea on what or how to chose a diode for it. It is for a uni project and we are being marked on our justification for choosing the diodes. Is there such ...
0
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3answers
95 views

Can voltages be different if watts are the same? Does DC vs. AC change this?

I'm currently building a home in a van, it's my first tango with electrical engineering. I watched a video on voltages and amps and my understanding is basically like so: a battery is like a water ...
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1answer
65 views

DC-DC power supply module help needed [closed]

I have purchased this little brick (link below) that I though would allow me to input for example 12V DC and output a lower output voltage, for example 5V DC, but I'm now testing it and it seems to ...
0
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6answers
162 views

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 ...
0
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1answer
82 views

Op amp based DC-DC voltage doubler

I have a LM471 op-amp and a single DC 5V source. Is it possible to double the source voltage using this op-amp? Can the op-amp be powered by the very singnal to be ...
0
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2answers
53 views

Crude simulation of a dc motor

I have a 24V battery bank and would like to discharge it in order to test the performance of different solar charge controllers. Eventually the batteries will supply a 2hp (1500W) DC motor and it is ...
0
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2answers
51 views

Can I use aluminum tape or naked two paralleled striped cables to connect parallel LED strips?

I need to parallel connected couple dozen cut LED strips. The total current reaching them won't exceed around 2 amps. My constraint: I can not order any more components for the job. My tools: ...
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3answers
138 views

Is there a way to adjust the DC Voltage

I have a source (1) of power which can be adjusted from 1-5 Volts and 40 mAmps. I have another source (2) of power which delivers a constant 5 Volts and 400 mAmps. I want to build a circuit which ...
0
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2answers
66 views

Power and control 3 phase ac induction motors with dc source

Background So we are making a drive system to be used in a medium sized catamaran. The catamaran will use two water-jets powered by two 3 phase 380v ac induction motors. The entire system will be ...
0
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2answers
57 views

Using a DC Power Analyser properly

In the context of an academic project, I designed a PCB which includes an MCU (EFM32), a GSM module and a GPS module. One of the main target was for the system to be low power. However, now that it is ...
0
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0answers
52 views

automotive positive negative and ground and switch connection

I am wiring auxiliary light. I want to use my oem switch (momentary) and replace the included push button. I've blew a few fuses, so it's probably better to ask here before I blew up more stuff. I ...
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1answer
113 views

Does current change when going through a DC voltage source? [closed]

Can you get the equivalent resistance of two series resistors if there is a DC voltage source between them
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2answers
42 views

Identifying multipleDC trains on the same track?

I'm modifying my DC train system to control the trains from a small chip onboard (arduino or spark core) and I want the trains to be able to know where they are and the controller to know where they ...
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2answers
75 views

Estimate current through inductor in DC circuit with PWM control

I am designing a circuit to control an electromagnet (coil with iron core) through a N-channel MOSFET driven by a PWM signal. I can't figure out how to derive the relationship between the PWM duty ...
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2answers
61 views

Charging li-ion batteries with protection circuit

If i'm using a protection circuit like this one: http://www.batteryspace.com/pcbfor148vli-ionbatterypack5alimitwithfuelguagesocket.aspx and 4, 3.7v li-ion batteries. Can I use a simple 16.8v dc ...
0
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1answer
73 views

Unable to Power Arduino and DC Motors via 2 AAA Batteries

I am using 3.7 V 2000mah battery. I am stepping it up to power an arduino board via an NCP1402. It has a continuous output current of 200mA. I am trying to run two Micro Metal Gear motors with stall ...
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2answers
111 views

Options for 12v battery pack with charger

I have an amp that requires 12-20v dc power. I'm looking into a solution for a portable battery pack that I can charge while running the amp as well with discharge and overcharge protection. This is ...
2
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4answers
115 views

Whats the point in conserving electricity if the AC current produced cannot be stored?

If we cannot save the ac current produced in a battery or some device like the DC current there is no point in conserving it because current once produced should be consumed somehow!! My faculty said ...
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0answers
57 views

Selecting motor for a DIY wheelchair stairlift

I need to make an wheelchair stairlifter for my stroked mother similar to : So I need to find out one motor in range of 200 Wat for lifting a 200KG load in slope of 43 degree from these options: ...
0
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1answer
114 views

Over heating H-bridge MOSFET (irf9540)? [closed]

I have done the circuit in the picture : from here (modified Question): So two LEFT MOSFET (IRF9540 & IRF540) will be overcharged and so heating and DC motor speed is Constance and don't ...
0
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2answers
122 views

Latching solenoid control

I am working on a personal project that will involve driving a latching 9V/DC solenoid from an arduino. The circuit I've come up with is dependent on two things, that I haven't quite figured out yet: ...
2
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0answers
67 views

DC-circuit with N-JFET transistor

My task is to decide RD and RS in this circuit: The properties of the N-JFET are Up = -3.5V and IDSS = 10mA. The criteria here is that the operating point should give UDS = 7V and ID = 5 mA. With ...
2
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1answer
126 views

DC Power supply Jack connector pinout

I'm trying to make a footprint for this connector: But I have a trouble about pinout. What is the SLEEVE TERMINAL, TIP TERMINAL, SHUNT TERMINAL? What is my power connection? V+ and GND?
0
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3answers
72 views

Switch 15V source with a MOS by digital 0/5V (dc)

I'm trying to switch on and off some 15V devices from Arduino Uno digital ports (0/5V). Each port must control a group of resistive loads (lights) of a train model. There are about 10 groups of loads, ...
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2answers
269 views

Filtering DC offset of a pulse train

How can I filter a DC offset of a pulse train with an RC circuit? The signal is a pulse jumping between 3.07V and 3.53V. But I need a pulse which is jumping between 0V to 0.5V. How can I filter that ...
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2answers
57 views

How to transfer electrical power from stationary to rotational part.that can be used for POV display?

I have been researching how to transfer electrical power from stationary to rotational part. Some of them showed the means by using slip spring rings like in this website ...
0
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2answers
81 views

AC vs DC and ELF - extremely low frequency

given : How do static fields differ from time-varying fields ? A static field does not vary over time. A direct current (DC) is an electric current flowing in one direction only. In any ...
0
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1answer
78 views

5v DC 1.0A micro USB device hooked to an 5v DC 2.0A charger [closed]

I've bought an Power Bank rated 5v DC 1.0A in it's input but it's extremely slow to charge via USB port, which provides an maximum of 500mA as i read in internet. I have and outlet USB phone charger ...
1
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0answers
74 views

Application of Fourier Series in Circuit

I am trying to find \$v_o(t)\$ in the circuit below, where $$v_s(t) = 3 - \frac{6}{\pi}\sum_{n=1}^{\infty}\frac{1}{n}\sin2\pi n t$$ The correct answer is $$v_o(t) = \frac{3}{2} - ...
0
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1answer
144 views

Is it safe to parallel connect components to a single to a 12v DC PSU?

Prerequisite: For a home-decor project, we wish to work with different LED strips and even a larger LED chip as a central lighting source by attaching everything to a powerful, high quality 12v CC/CV ...
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2answers
48 views

Relay - Datasheet Max DC Voltage

This may seem like a dumb question, but I want to be sure. In the below datasheet, what is the DC voltage the relay can handle? I am assuming it is the ...
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1answer
73 views

Driving a 4.5V motor with PWM from an Arduino

This is a basic question but I would appreciate help. I have: An Arduino A 4.5V DC motor Various transistors, like BC337, 2N7000, 2N2222A What I'm trying to do is very simple: control the motor ...
0
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3answers
64 views

Using a motor with DC

I am using a Lego DC motor with a 9V battery which can provide up to 1A of current. I called Lego support and they said the motor draws 300mA of current. What does that mean? If I plug the motor to ...
0
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0answers
62 views

Stacking DC-DC converters

I'm currently building a high-power LED driver to be powered from a 2.7V supercapacitor. To this end, I'm seeking a solution with high current rating (up to 3A, so ideally a controller IC rather than ...
0
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3answers
136 views

What happens if I supply a higher voltage than the rated voltage of my jack?

I want to replace the original jack from my notebook with a new one since it is broken (and I would like to avoid to replace it with the same as the original). The original AC adapter supplies 19V and ...
2
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1answer
77 views

Determine the maximum load of a power supply

I am trying to upcycle an old bit of tech I had lying about. The main part I am looking to recycle is the power supply however I do not have specs of the power supply itself. I have measured an output ...
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1answer
65 views

voltage sources in parallel without any resistors [duplicate]

![two dc voltage sources are in parllel & they are grounded.so what reading voltmeter will show? ][two dc voltage sources of different voltage are in parllel & they are grounded.so what ...
1
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1answer
92 views

Current flow in AC vs DC

If a live wire is taken from AC and connected to a bulb, while the other terminal of the bulb is connected to ground, the bulb glows; but if I take the positive terminal of a battery (DC source) ...
0
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2answers
190 views

How does this circuit give DC output?

I don't understand how this circuit works. I'm not sure if it's correct. It should give a DC output, but how would it do that?