Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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.

0
votes
2answers
67 views

DC motor characteristics

I have a PM DC motor. I am controlling the motor speed using PWM. I wanted to know what is the relation between the torque vs dutycycle and speed vs dutycycle for the motor( given the fact that the ...
1
vote
3answers
119 views

Can I use a 12v 20A DC switch for a 24v 10A DC load? [duplicate]

simulate this circuit – Schematic created using CircuitLab I have a toggle switch that is rated for 12v 20A (240 Watts) and I have a load from a battery that I want to turn on or off with this ...
-5
votes
1answer
48 views

AC/DC power supply module with 20mA output current

i want get 20mA current with 24V ac to dc. I have found this power supply module with 6-9A output current but i need max 20mA. What can i add with this module to achieve my settings? I am powering ...
0
votes
3answers
73 views

DC 3-12V Water pump connected to power source doesn't work

I'm trying to make a simple connection of 3-12V Water Pump to a power supply(https://www.amazon.co.uk/dp/B07D3XS91J?ref_=pe_1365641_54848841). I'm using power supply which is 5V (https://www.amazon....
1
vote
0answers
25 views

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, ...
1
vote
2answers
42 views

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 ...
0
votes
1answer
57 views

How to chose between 9V or 12V (or others) DC power supply [closed]

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. ...
0
votes
0answers
52 views

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 ...
5
votes
5answers
3k views

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 ...
8
votes
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 ...
0
votes
2answers
71 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 ...
1
vote
2answers
43 views

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 ...
0
votes
1answer
37 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 ...
2
votes
0answers
78 views

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 ...
0
votes
2answers
59 views

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 ...
0
votes
5answers
211 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 ...
0
votes
3answers
85 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 ...
0
votes
1answer
81 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 ...
-1
votes
1answer
60 views

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 ...
0
votes
3answers
93 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 ...
0
votes
0answers
31 views

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 ...
0
votes
1answer
75 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 ...
0
votes
0answers
50 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 ...
0
votes
2answers
142 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 ...
0
votes
1answer
68 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 ...
0
votes
2answers
74 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 ...
0
votes
1answer
65 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 ...
1
vote
1answer
63 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 ...
5
votes
1answer
108 views

PCB Mount DC Connector /Jack

Why does this DC connector have holes at the ends of the pins?
0
votes
0answers
48 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 ...
0
votes
0answers
66 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 ...
0
votes
1answer
45 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 ...
0
votes
1answer
57 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-...
-2
votes
1answer
70 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 ...
0
votes
2answers
87 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 ...
0
votes
1answer
122 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, ...
0
votes
3answers
281 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 ...
2
votes
2answers
248 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 ...
0
votes
0answers
36 views

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 ...
1
vote
3answers
95 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 ...
0
votes
2answers
57 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....
0
votes
0answers
21 views

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 ...
0
votes
4answers
73 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). ...
0
votes
3answers
145 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 ...
0
votes
1answer
29 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 ...
1
vote
2answers
97 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 ...
0
votes
1answer
65 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 ...
0
votes
1answer
66 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 ...
1
vote
1answer
48 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, ...
0
votes
1answer
86 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 ...