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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DC-DC Converter 48VDC to 12VDC [on hold]

I Plan to make buck converter that converts 48VDC to 12VDC 25A. Is there any IC in the market that can make this happen? Thanks in advance!
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3answers
99 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 ...
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1answer
60 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
57 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 ...
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1answer
73 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) ...
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2answers
40 views

What is the difference between a 2 and a 3 solder terminals socket (coaxial jack dc)

I'm not pro with electronics and electricity and I want to replace my notebook socket so I'm looking for a coaxial jack dc socket but, as I only have two cables (a positive and a negative one) to ...
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27 views

Using 3 Channel Video Switcher Module with Arduino

Hey all I am wondering how to go about switch from camera 1, 2 or 3 using this 3 Channel Video Switcher Module on ebay here. Since there's only V+, V- and signal for the "switch" it looks to take a ...
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0answers
36 views

What AWG wire should I use to connect RGB Signal Amps to LED Strip?

I am wiring in some 5050 RGB LED strip lights in my basement. There is a small utility room adjoining and I'm keen to keep the transformers and signal amplifiers in there in order that they can be ...
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1answer
48 views

DC Motor Coil Voltage

I have a DC stepper motor that appears to be powered by 75V supply voltage (I measured this). However after connecting the motor to the controller (supply), I measured the voltage across the coil ...
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1answer
58 views

Why should I use DC coupling when I'm finding the frequency response of a circuit?

In my last electrical measurements lab I was asked to plot the frequency response of several different filters (high pass, low pass, and band pass) using an oscilloscope. My professor told the class ...
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2answers
52 views

Set ground reference of a 5v DC power supply to the middle of a 24v DC power supply

I have 2 isolated AC/DC power supplies. one generates a regulated 5 volt power supply and other generates a 24 volt power supply as you can see in the picture below: I also have designed a circuit ...
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3answers
63 views

Can I use a switch rated as 250VAC 25A to switch 50VDC 25A?

I am looking for a switch that can handle 25A continous current, the voltage will be maximum 50VDC, most often about 46VDC, and it will be used to switch on two dc-dc converters that have no load ...
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2answers
79 views

How do I drop 19VDC from a 0-60VDC source to get an accurate linear 0-48VDC signal

I've been using the Stack Exchange website for years, but never asked or answered a question, so first I'd like to say thank you for all of the help over the years. On to the problem: I want to ...
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3answers
76 views

Connecting parallel DC loads

Consider the following power supply interface. I'd like to power a number [1,N] of bitcoin miners, 12V, 5A each one. question is: do red wires must be connected with V+ pins ? do black wires must ...
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39 views

Designing a Solar Diorama with Motor and LED Indicator

I'm trying to design a Solar Diorama that uses Solar PV panels to power a small spinning motor and an LED indicator light that will show the current amount of power. Motor: 12 Volt DC, 2.1 Amps, 25.2 ...
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3answers
65 views

Low voltage adjustable DC power supply (0.1 to 0.75V DC) @ 300 mA

I need to create an adjustable DC power supply that can output between 0.1 and 0.75V DC at 300 mA (possibly as little as 100 mA). My input voltage can be anything, including +/- rail. Currently I am ...
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0answers
56 views

Stepper motor to replace brushed DC motor to be used to start a gas engine?

I'm trying to decide if it would be possible to use a stepper motor to replace a current 12V DC brushed motor that is used to turn over a small (~149cc) gas engine for starting. The reason why is, I ...
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0answers
62 views

DC current amplification

i'm trying to design a battery charger for 5Ah li-ion battery. Due to cost management problems, i am not able to use advanced 5A charger controller ICs; instead, i am going to use a 1A controller with ...
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2answers
70 views

How do we predict if power loss will increase or decrease in a DC circuit?

I want to know whether it is possible to predict if power loss will increase or decrease in a circuit with a fixed EMF, a fixed resistor in series and a variable resistor in series. If we change the ...
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1answer
23 views

Amperage for Sony SNC-VB630 Camera [closed]

I am trying to choose a right DC adapter for SNC-VB630 CCTV Camera but the only specs I could find in the official documentation was 'INPUT 12V DC'. Nothing about amperage. I have a 12V dc adapter ...
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0answers
52 views

PWM and brushed DC motor - AC input? Limiting RPM?

I'm looking to replace the 20-year old poorly-performing speed control in a MIG welder. It allows the user to adjust the speed of a small brushed DC motor, which drives thin welding wire of of a ...
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0answers
62 views

Calculate current in an series RC circuit with a DC square wave source?

Am still a noob in electronics so bare with me, In the image bellow how is the voltage drops found and the current in the meters, what is the formula? and if instead of a capacitor an inductor is used ...
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1answer
40 views

Electronics by Example [closed]

I am interested in learning more about electronics. I know some basics about resistors, capacitors, transistors, and diodes. I would like to learn more about things such as operational amplifiers, ...
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1answer
36 views

Voltage wave form across a DC motor driven by a transistor with pwm

Above is the simple implementation for a DC motor control with pwm. I was expecting to see a square wave with a Vmax when Q1 is ON and zero when Q1 is OFF like the one here: standard pwm But ...
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1answer
81 views

Measuring Current in 12V DC Fan

I am trying to measure the current of a DC computer cooling fan (Intel E18764-001) at various volts. Its rated specs are: 12V 0.20A. Check it out here. So I am suspecting that this is telling me: ...
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1answer
101 views

Calculation of base current resistor resistance for a transistor operating in switch mode? [duplicate]

I have a 9V DC motor and I want to control its speed with an Arduino board with help of a power transistor TIP120. In one of the web-tutorials the writer explains how to calculate the resistor ...
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3answers
185 views

What is the advantage of a switching over a linear power supply?

I want to build my own switching power supply. I already know how to make a 10 Ampere Linear supply, and I'm wondering if I should bother. What do I have to learn to do a switching supply? What makes ...
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3answers
581 views

Locking up a DC motor with constant supply a bad thing?

I am working on a little pen plotter project and for one of my motors (which supports the pen) I have used a small DC motor obtained from an old DVD drive. I have noticed that if I supply a constant ...
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4answers
100 views

How to measure DC Operating Point of a simple transistor circuit

Could someone explain to me how to find the DC Operating point of this circuit? I need to find it by running a simulation and probing the circuit, not solving for it mathematically, and I'm not sure ...
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1answer
94 views

Charger light circuit [duplicate]

I have a charger light. It gets charged by 220V AC supply. It can light 5 LEDs. I know that it needs to make the supply 220V AC to DC of lower voltage nearly 5V to 10V. Then it can charge the small ...
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0answers
57 views

Custom USB 7 port hub PCB dasiy-chain

I had a schematic laid out for a custom USB 2.0 7-port hub I needed to create for a project of mine. It currently uses Ethernet RJ45 sockets to provide power and data to each hub (2 Ethernet ports for ...
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28 views

Can I use a power adapter with the same output voltage but different amperage? [duplicate]

I unfortunately burned out a DC adapter for my alarm clock while traveling in Europe. Evidently, it didn't take the 220V well. I ordered another one on Amazon and it just arrived with two problems: ...
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1answer
189 views

Convert DC 1.5V to 2.7V [duplicate]

How can I convert DC 1. 5V (R20 cell) to DC 2.6V with as much as possible amps? I would like to charge 500F supercapacitor with it. (I can use only 1 R20 1.5V cell).
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1answer
70 views

How to ON/OFF two fans with 3-state rocker switch?

I have a 3-state switch, It has 3 pins. It can have 3 state as you can see in the picture below. when it's off (i.e on O) the middle pin is not connected to ...
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2answers
60 views

Bias headphone audio signal for use with digital potentiometer?

I am attempting to control speaker volume via a digital potentiometer, the problem being that audio signal goes both above and below 0V, for regular potentiometers this is no problem but for digital ...
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3answers
72 views

Can I use this relay for DC

http://www.dx.com/fr/p/ssr-25da-25a-solid-state-relay-white-134494#.VDmPWPl_uap It says AC output but how can this transform DC to AC ? Shouldn't this act like a switch ? If my circuit is DC and I ...
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2answers
62 views

frequency of DC current

What is the frequency of dc current, Please tell me, why frequency of DC current is zero in detail. Thank you. I hope anyone really tell me .
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4answers
170 views

How do I find the voltage range for an unknown DC motor?

I have a small unmarked motor with a burned out speed controller board. I'm able to figure out that the motor is a DC motor because it has two wires coming out of it and there's a rectifier on the ...
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3answers
98 views

Effect of non-inverting op amp on the AC and DC components of the input

I was wondering what the effect of an op amp like the one in the image below is for an input signal such as \$0.5\sin(2000\pi t) + 0.5\$ V? Are the DC and AC components amplified with the same gain? ...
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1answer
121 views

Commanding a 12V DC motor with high power (~20A)

I'd like to control a 12V DC motor but it has very high power, around 20A. I was looking for H-bridges but they all support only low power (around 1A) Do I have to build my own H-bridge with high ...
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1answer
82 views

Participation of DC component in total average power of signal

My task is to calculate participation (in percent) of DC component in total average power of signal from photo: I represented this signal as complex Fourier series: ...
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2answers
91 views

adding fluctuations to 5V

hobbyist here, hope someone can guide me. I'm using I2C (only have 4 wires{PWR, GND, SDA, SCL}) to communicate with two exterior Circuit (Circuit A, and Circuit B, both have MCUs), which can be ...
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1answer
153 views

How to replace bulb with LED in a PWM circuit (car)?

I want to replace a light bulb in a Peugeot 308 SW with a LED. The bulb works (lights) normally, but the LED blinks. I thought they are controlling the bulb in alternative current but my digital ...
2
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3answers
94 views

Splitting DC power supply risk?

I am looking into taking the power supply 12V output of my PrintrBot and plugging a very simple parallel circuit with some LEDs. I know I can connect a parallel circuit similar to this Splitting a ...
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2answers
320 views

How to make a 12V DC variable voltage supply with more than 30A output?

I have a SMPS capable of outputting 33A at 12V and I would like to make it have a variable output with full current potential, or close to it. Now, Is it possible to do it with a PWM-controlled ...
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3answers
168 views

What does an inductor's current stabilize to in DC?

As you can see from the below graph, after an inductor is turned on, the current is stabilized to approximately 6.5mA. My question is: what does the 6.5mA represent? Where did that number come from? ...
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1answer
154 views

Help me hack this speaker, where would I introduce DC voltage

I have a speaker that runs off of AC (there is a switching converter within the speaker) I'm attempting to convert it to battery power, From my understanding the speaker runs off of 5V (someone else ...
2
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1answer
67 views

Difference between DC operating point and Transient operating point

I've been simulating a circuit using synopsys and I'm just wondering what's the difference between DC operating point and Transient operating point?
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3answers
77 views

Electrical resistance converted to wire temperature

I'm trying to get a formula that I can reuse to help me determine wire size and properties. The goal is to heat a 430' wire between 40-100F using 12 volts and 10 amps of direct current. Everyone is ...
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1answer
28 views

Cumulatively excited and Differentially excited DC generator

Is a cumulatively excited DC generator long shunt or short shunt motor?