Electrical Engineering Stack Exchange
Electrical Engineering 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, and dynamos.

DC stands for Direct Current which means the flow of electric charge in a single direction, as opposed to Alternating Current which means the flow of electric charge continually switches direction at a particular frequency.

DC is generally used in low-voltage applications for powering (control) circuits used in many gadgets and electronic systems.

Examples of DC sources are:

  • batteries
  • solar panels
  • dynamos
  • thermocouples
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Wiring a DC socket - why three pins?

I have this DC socket: Which I intend to wire up to a circuit to provide power. I have a DC power supply which has a positive tip polarity. I'm good to go and wire up the socket but I am a little stuck as there are 3 pins on my socket. From the…
Andy Smith
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Simple circuits 1.5 V DC to 9 V DC

Anyone got any super simple circuit designs for converting 1.5 V DC to 9 V DC? Maybe something that uses a couple of transistors would be good?
Jim
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Voltage Divider Supply (Unloaded and Loaded)

The loading down of a system is the process of introducing elements that will draw current from the system. The heavier the current, the greater is the loading effect. This is the the highlighted definition in my book in describing the term…
Shane Yost
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Canon no longer makes CanoScan 8800F AC adapters, help needed to replicate its functionality

The CanoScan 8800F uses a proprietary 32VDC AC adapter that's no longer manufactured. A Flickr user did the trial and error to find out how to modify another 32VDC AC adapter for use with the 8800f. It seems simple enough. One pin carries the 32VDC…
enigmaticeasteregg
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Will a DC circuit breaker trip due to high voltage?

Will a DC circuit breaker trip due to high voltage (exceeding voltage rating) or will it only trip because of high current? For example, if you have a 40 Amp DC circuit breaker which also has a 32 voltage rating would you have to keep the amperage…
Chris U
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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 voltages V1 and V2 end up being added together? Could you…
Marvin
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What watt rating will this resistor need?

I am setting up my home security system. It calls for a 5.6 ohm resistor at the end of the line with smoke detectors. Does it matter what wattage? Can I get by with 1/4 watt?
C.W.
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Determine the current through a voltage source for nodal analysis

I'm struggling with a problem our professor gave us, which states: "In the following circuit, find the value of the resistor R_x so that the power consumed by the resistor R1 is the maximum." simulate this circuit – Schematic created using…
lightspot21
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Help needed to identify pins of power supply

I could find no schematic nor data sheet online for what appear to be DC power supplies. There are two terminals on the smaller ones labeled output +, -, three pins labeled input 1, 2, 3 and a lone pin labeled INH. The larger boards are nearly…
Jean-Paul McCoy
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Combining 2 or more DC sources

This is a fairly general question with no specific example in mind as I was just thinking about the problem, but was unable to find any answers on the internet (probably because I am not asking the right questions). I will however give a…
Ant
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DC power through a female socket

I have a solar panel and I would like to use an extension cord. I know this works (heavy duty extension cord) but the guy cut the ends off of the cord to just use the wire (see video links below). I don't want to do that. I would like to add a…
user45481
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1-pole and 2-pole DC circuit breaker

My question is rather simple, when and why do one use a 1-pole or 2-pole circuit breaker in DC (+24VDC and GND)?
JavaCake
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How to wire a 12V DC fan to a Molex connection?

I have a 12V DC fan with two wires (black and red). I want to solder it to a Molex 8981 connection (powered by an ATX power supply). Here are the details for the connection: I'm guessing the fan's positive red wire goes to the +12V yellow wire, but…
Louis Waweru
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AC and DC voltage source

Why do we consider DC voltage source as short in AC analysis? There is some explanation in Malvino's book but I am unable to understand, can somebody explain this in a lucid manner?
Sayan
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Need a choke coil inductor for DC welder

Working on making an AC 225 volt welder into an AC/DC welder (225 volt AC and 125 volt DC). I purchased bridge rectifier for 225 amp and 220 volts. I am going to use two 3500 uF capacitors and a choke coil on the DC side. I need to build a choke…
Terry Miller
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