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Questions tagged [dc]

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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How to calculate or show in matlab/pspice the DC component from a circuit simulation?

Based on Pspice I'm simulating this RL full wave rectifier That gives the next voltage and current output at the showed probe point The idea is to extract the DC component of the current or voltage, ...
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Connecting two wires to a DC 12v port on a controller board with 4 pads for a monitor

Sorry, the question was difficult to word. Basically I recently bought a controller board for a monitor and the DC cable I got wasn't correct. So until I get the right part, I just want to test the ...
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How to chose between 9V or 12V (or others) DC power supply [on hold]

I see a lot of devices working either with a 9V DC input or a 12V DC input, usually provided through a DC jack connector. I was wondering about advantages and/or inconvenients of both voltages. ...
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Advice for PCB layout 230V AC to 18V DC with another function (beginner continued)

I am continuing a thread Beginner's second PCB circuit design: AC to DC Does this PCB design look better than the previous and do you understand it? I also want to know if the terminal blocks ...
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5answers
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Beginner's second PCB circuit design: AC to DC

I am designing an AC to DC converter and I just want to make sure that I am so far doing the right thing — placement of components and wiring etc. — as I am a beginner. Does this look ...
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5answers
1k views

Switch for DC application

I have two solar panels in series totaling a maximum of 80 VDC and 500 Watts. I believe that would be a maximum of 6.25 Amps. Could a 20A 120/277V AC switch handle that since 6.25 Amps is a ...
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29 views

AC/DC Converter isolation transformer, where to buy? [closed]

I have been wandering around with the thought of designing my own AC/DC step-down converter to save cost instead of buying ready step up/down converters. I need to have a small form-factor ...
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68 views

DC Barrel - Powering a battery pack

I am looking for a DC barrel to power a battery pack. The battery in question is connected in 10S3P, that's is a nominal voltage of 36V. I am currently looking for a DC barrel that can withstand at ...
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2answers
34 views

High temperature electrical heater [on hold]

I've been trying to put together a relatively simple electrical circuit to heat an electrode to 750 degrees celsius. In theory, is it simplest to persist with using several car batteries (not those to ...
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2answers
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How does the power efficiency of an appliance compare using 12V DC or 240V AC with an inverter?

With an off-grid system, if an appliance supports powering via both 12V DC and 240V AC, is there any difference with the power efficiency of either method excluding the draw of an inverter used to ...
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1answer
33 views

Linear regulator operating point over input DC Sweep analysis

I'm sweeping the linear regulator input voltage on DC using Spice from 0V to maximum expected Vin. However, as the OTA that makes part of LDO is internally supplied by the output voltage, the ...
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Way to power a monitor that requires 12 V 2.5 amps with a PC USB port [closed]

I am looking to see if there is a way to power a monitor like this: (https://www.amazon.com/gp/product/B07774L6TT/ref=ask_ql_qh_dp_hza) over one (or two) of the PC's USB ports, so theoretically it ...
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Can I run DC voltage through RJ45 Connector with Magnetics?

I am designing a PoE (Power over Ethernet) application. My question is can I run 48V DC Voltage through a standard RJ45 Jack WITH Magnetics? or do I need one WITHOUT magnetics? I am planning to use ...
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5answers
187 views

Why do we use alternating current and not direct current for mains power plugs within a house? [duplicate]

I understand that for transporting electric energy it makes way more sense to have AC. But within my house, I don't think that argument holds any more. Devices I use (roughly ordered by power ...
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3answers
82 views

Does voltage and current have an inverse relationship in DC power transmission?

Let's suppose that we want to transmit a 1kW via DC generator with the below voltage level. From this we can see that the relationship between the DC voltage and current is inversely proportional, P ...
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1answer
64 views

Current limiting a starter motor

I'm planning to try to build an electric go-kart. My idea was to use a 12V starter motor from a car to power it, since used ones are fairly cheap and easy to get. (I already have 2 of them to ...
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Building a LiPo battery pack for output 270v DC

so this is related to my other question if anyone wonders. I’m building out a EV battery pack to boost charge a vehicle in real time during heavy duty cycles. The vehicle currently has no external ...
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3answers
85 views

CCTV camera running 700 ft [closed]

I an trying to run a CCTV 5mp camera from the end of my long driveway to my DVR. Using RG59 18/2 awg 700' 12v dc. I get some voltage drop when IR LEDs turn on at night and makes the camera turn off. I ...
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Can a MTS 101 2 pin ON-OFF switch rated for VAC be used in a DC circuit?

I'm currently looking at buying a bunch of MTS 101 rocker switches which are rated for: AC 125V 6A, AC 250V 3A For DC the rating is not available http://www.massuse-relay.com/details/MTSSeries.pdf ...
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1answer
70 views

270v DC current limiting circuit

I have looked through some of the current limiting responses, but don’t see any close to what I’m working on for my project. I have an EV system running in around 200 - 270V DC. I want to build a ...
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45 views

DC signal detection

I have a current source that can output different types of waveform depending on the input, including DC (Howland current pump). I need to find a solution as to make sure that when DC is not required ...
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2answers
137 views

Capacitor Voltage during Transients

I am starting to learn transient analysis series RC which requires our own equations to be derived, but I don't understand how the voltage across the capacitor is given in the equation below from a ...
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43 views

Input protection on a DC jack

I am designing an battery powered instrument with around 20-40Ah 3S li-ion batteries in it along with a 10A 3S(12.6v) external charger. Due to ease of availability and the current capacity I have ...
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2answers
71 views

Avoiding DC voltage drop for surveillance cameras over long distances

Trying to power 2 HD-TVI cameras 800 ft away from my home office. The wall mounted adapter provides 12v DC at 1 amp. I am looking for a good solution at the lowest possible cost. There are ...
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1answer
56 views

How do I combine 3 batteries in series and parallel with different outputs?

I'm looking to combine the 2 circuits shown in the picture below using a switch.(ON-OFF-ON) I would like to keep the 12V output seperate from the 24V output. This is to maximize efficiency when using ...
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1answer
48 views

Automatic Power Selection with MOSFET

I need a circuit which will automatically disconnect the battery from LOAD when ext. DC power is connected so that the battery won't get damaged. Theoretically a pair of diodes can solve this but ...
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1answer
98 views

PCB Mount DC Connector /Jack

Why does this DC connector have holes at the ends of the pins?
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45 views

Thevenin Equivalent circuit, concept question

I am looking at the circuit in: Apply Thevenin Theorem to a circuit with 2 sources? The circuit and its equivalent have been given as follows in the thread: Circuit: Thevenin Equivalent: Instead ...
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0answers
60 views

What calculation can be used to predict the voltage across an air gap as a plasma spark discharges over 1ms?

I am trying to determine what voltage and instantaneous current is available if using a spark gap in air or other gas. Comparable to an auto ignition. This will be DC current. There will be a main ...
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1answer
41 views

Difficulty sourcing a 6mm dc adapter/plug/converter…any ideas?

I recently bought a second power supply for my laptop. The laptop requires a 330w power supply (it runs a desktop grade CPU), which costs around £120 (Laptop is the Asus GL702ZC). I managed to source ...
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1answer
55 views

12 Volt DC Power Supply set up

Can I connect a 12 volt DC regulated switch mode power supply (good voltage control) in parallel with a 12 volt DC car battery (great amp supply) to supply the extra current need to run my RF-...
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1answer
68 views

converting 80Vdc to 50Vdc

I am working on a project that requires an existing power supply outputting 80VDC @ 60A to be reduced to 50VDC. Current is not really an issue in the application. Does anyone have any useful ...
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2answers
82 views

What are the practical differences between AC and DC transmission?

I have a long (2m) but thick wire between transformer-based power supply and low frequency power amplifier. Know your best advice ahead, but no, I cant get rid of it. I can put it in two ...
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1answer
116 views

What type of motor is this? (photo included)

I want to make this motor work, but I can't understand what type this is. I supplied 5V DC to the terminals, but it just kept buzzing and the coils were energized. It also had some kind of circuit, ...
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3answers
128 views

Converting 220v 50Hz to 110v 60Hz

I have a situation which I'm not sure how to handle. I've purchased an appliance from US. This appliance is powered by electric motor (175W) and then I realized I cannot use simple step-down converter ...
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2answers
187 views

Why do engineers usually short ground and negative ports on a DC power supply?

I'm fairly new to electrical engineering, and have seen many DC power supplies where someone has shorted the ground (green) port with the negative (black) port. From my understanding, the ground is ...
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DC Voltage Multiplier for Positive and Negative Input

I have a small DC motor being driven by a controller which supplies +6V/-6V to the motor to control its speed and direction (elliptical machine resistance control motor). The issue is that 6Vs is not ...
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3answers
89 views

Simple Non-Inverting Op-Amp Problem

I am trying to double the voltage out from a 1.5V battery using an MCP618 op-amp as a learning experience prior to using the op-amp to amplify the output from a set of strain gauges set up in a ...
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2answers
47 views

Op Amp Output Voltage

I have a question about an LM741 op amp IC. I am using the op amp as an comparator (open loop with no feedback), as seen below: When the op amp output is low, the output voltage is still around 1.2v....
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How to apply Thevenin's theorem in multivoltage(3) sources?

Here is a question I am not able to tackle as the requirement is to solve it by Thevenin's theorem. The question is to find the value of current passing through 20 ohm. I can perform Mesh analysis ...
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4answers
68 views

Multiple Buck Converters

I have multiple buck converters, model XL4005 (datasheet ), fed from a 12V battery source to several devices i.e. My motors (require 12V), Arduino (requires 5V) and Transmitter module (require 3.3V). ...
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3answers
138 views

Building AC to DC circuit that can not be run on a breadboard

First I have an AC power source. Can I solder the power source directly to a rectifier to make it DC? I plan on using a protoboard using the DC power but I need the board to be able to handle 2Amps ...
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1answer
18 views

Solar Panels: Charge Batteries via MPPT Charge Controller *AND* Power PV-Direct Load At Same Time?

I have two 290 watt panels in series that are currently used to charge a 48V battery bank via a MPPT charge controller. The run from the panels to the charge controller and batteries is about 70', and ...
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2answers
68 views

Is my understanding of this level shifter correct?

I am considering using this TI LSF0102 level shifter in my circuit - but would like to understand, based upon its datasheet, if I have my understanding correct. My aim is to be able to supply 3.3V ...
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1answer
64 views

LED Lightbar as a turn signal [closed]

I changed my turn signals to LED light bars the other day. They are completely legal, but the issue I'm having is I can't use my parking lights and turn signals. The bulb that I took out and replaced ...
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1answer
63 views

Buck converter analysis

I have to reverse engineer a PCB of a buck converter and figure out the component values. Given is that Vin = 15-20V and output is ...
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1answer
46 views

BJT-piloted MOSFET circuit: Feedback requested

I had the idea to make a power converter, and I would like some feedback. I can take constructive criticism. The basic idea was to make something where a microcontroller could drive a power MOSFET, ...
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1answer
82 views

How does freezing temperature affect electronic equipment?

What happens if you put a simple circuit like a timer with a 555 IC and, let's say, a DC motor, including 3 AAA batteries in a freezer (around -15 centigrade) in a working state? If it does harm the ...
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1answer
37 views

Why does the TUF formula use \$V_{rms}=\frac{V_m}{\sqrt{2}}\$ and not \$V_{rms}=\frac{V_m}{2}\$ for a half wave rectifier

We know that for a half wave rectifier \$V_{rms}=\frac{V_m}{2}\$ and \$I_{rms}=\frac{I_m}{2}\$ But the Transformer utilization factor uses \$V_{rms}=\frac{V_m}{\sqrt{2}}\$ (But uses \$I_{rms}=\frac{...
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2answers
79 views

230vac / 5vdc power supply design

I am making my own basic bench power supply mainly for testing logic gate circuits, relays, flip flops etc, that I can move around to different locations. The circuit of the entire schematic will be ...