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.
2
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2answers
83 views
DC/DC Converter minimum load?
I'm using the NTE0506MC DC/DC converter which boosts 5V to 6V. The output voltage I'm measuring with no load is 9V not 6V. In page 3 of the datasheet they mention that it needs a minimum load of 10% ...
6
votes
1answer
2k views
what will happen if i apply 220 dc voltage to 220 ac system (load) like lamp?
Please help me. Let say if I have a lamp which is operated on 220 V ac. Instead of applying 220 AC voltage I apply 220 DC voltage then what will happen? And if i want to convert this 220V dc to 220V ...
4
votes
4answers
74 views
What are the factors that significantly affect the life span of a DC motor?
I'm currently planning to run a DC motor continuously on solar power. So I would like to know which things I should be very careful about for optimum lifespan of the motor. I found the following two, ...
1
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1answer
67 views
AC DC Analysis of diode
in the following circuit:
Im looking to find what \$v_D(t)\$ is given \$V_γ = 0.7 V\$ and \$r_f = 0\$.
Now when doing the DC analysis, find that \$VDQ = 0.7 V.\$
But im having trouble finding ...
0
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0answers
50 views
Choosing the correct brake resistor for DC motor
I have a DC motor running on 24VDC rated 150W (~6,25A), how do I calculate the correct brake resistance?
1
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0answers
39 views
SEM Permanent Magnet DC Motor DPM 30R4 1500RPM 24VDC Output: 0-25kW & Brake
I am in the plannning stages of a project to build a pig rotiessiere. I have the above mentioned motor, but I am unsure of what type of power source is needed to run the motor and what can I do to ...
0
votes
1answer
46 views
Frequency of fluctuations in power in an input power design circuit
I am thinking about the following power design circuit in section 6.1 : http://www.arndaleboard.org/wiki/downloads/supports/BaseBoard_Specification_Arndale_Ver1_0.pdf
Is it possible to calculate how ...
1
vote
2answers
74 views
Providing DC power with failover DIY for IP camera
I'm building a simple battery backup box for a 5V IP camera. I've got a few options for battery, sealed lead battery or a mix of portable LIPO style "USB" power bricks. I've seen boards built for ...
1
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2answers
442 views
Common ground between battery and AC/DC adapter
Is it possible to connect an AC/DC power adapter's ground (-) to a battery's negative side?
I am powering a car radio with a 12V AC adapter. That works fine. However, if the radio loses power, it ...
0
votes
2answers
85 views
Battery powering an unknown DC motor
I know nothing about motors. I have DC motor (sealed in a casing) that uses 6v/12v 1a (mains switching power supply) with 2.1x5.5mm DC connector. It has variable speed controller, reversible ...
-2
votes
1answer
54 views
How much current draw will a dc-dc converter have in this situation?
I am trying to make a mobile computer for my Raspberry Pi. The problem here, is powering the Pi, screen AND the USB hub from the same power source. I have bought this: ...
0
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1answer
40 views
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)?
0
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1answer
59 views
I think I am looking for a specific DC relay switch
I looking for a switch not sure what kind though.
let me explane:
I have 2 sources one creating DC 12v, 2 one creating around 6v DC
One source works for about 12 hours each day then stops
the other ...
-1
votes
1answer
73 views
Will a 40W incandescent AC bulb operate on a 330V DC voltage?
Will a 40W incandescent AC bulb operate on a 330V DC voltage or not?
0
votes
0answers
41 views
Loading effect problem
i m trying to connect a de sauty's bridge(AC bridge) output to a precision rectifier. The problem is the output of the bridge (AC bridge) changes drastically to 5volts as soon as the connection is ...
2
votes
1answer
106 views
How to build “two power sources” in a microcontroller circuit?
My circuit has a microcontroller, it uses power from a DC transformer (120V to 12V DC). My circuit also control an pneumatic valve which also use 12V DC. Almost every time when the pneumatic valve ...
1
vote
1answer
604 views
DC restoration of a video signal
I have a composite PAL/NTSC video signal. One problem I am having is getting a reliable sync signal from it; picture brightness causes the sync pulse (normally 0.3V) to vary; so much that my scope ...
0
votes
0answers
41 views
DC circuit breakers in automation plant
I am currently working on designing the power grid of a automation plant. Since i already have a background in automation, the rule of thumb i usually follow is to have circuit breakers in front of ...
6
votes
3answers
2k views
Scale 30-50mv signal to 0-5v range
I have a CO2 sensor that output signal values 30mV-50mV. I need to translate these voltages to 0-5V for my microcontroller with the highest resolution. I understand that I can amp the voltage using ...
-4
votes
1answer
73 views
DC Current Regulator 24v [closed]
I am trying to connect solar panels to a battery and then add a grid tie inverter of 1 kW. If you connect the grid tie inverter directly to the battery it draws way too much current, gets too hot and ...
1
vote
1answer
237 views
Can I safely and efficiently connect batteries parallel to a DC source? [duplicate]
I'm building a custom radio system for a friend by using a car-audio setup built into a boom-box-like container. I have everything wired up, and it works well enough. In testing though, I've run into ...
0
votes
1answer
50 views
Frequency and magnitude of power variations in a DC circuit.
I have a 5 V 5 A power source which is connected to a simple development board with a processor that draw current dependent on utilization. I use a multimeter that measure 1000 samples / s to measure ...
1
vote
1answer
86 views
Electrical saftey of metal panel-mount DC jacks
Context:
I have a robotic arm with a series of servo motors, that together draw up to 3A from my bench supply (depending on the load on the servos). To make it easier to transport the robot around, ...
5
votes
5answers
5k views
12V DC UPS for Network Equipment
Many times we want to kept running low power devices like DSL modems, etc.
Most of these devices take 12V/9V DC so why to use ordinary UPS which convert AC to DC to AC, lots of conversion lots of ...
1
vote
3answers
133 views
DC adapter not supplying current
I'm trying to get .5 A of current from a mobile phone's DC adapter, which is within its rated specifications. I am able to detect a voltage of ~5 V DC between the power and ground wires, so it seems ...
1
vote
2answers
87 views
DC Voltage Grounded with AC Input
This is an image from a book showing us how to solve BJT circuits via AC analysis:
So I understand that when doing AC analysis to ground all the DC voltage sources but I don't understand why. Can ...
2
votes
3answers
93 views
Can supplying DC power into an AC device break the device?
I have an AC device that takes 12 volts 47-63Hz AC. It is a water softner that is essentially an electromagnet. I lost the original plug and supplied it with 11.2V DC, it came on for a few minutes and ...
2
votes
4answers
2k views
How to tell polarity expected of a DC barrel jack?
I'm sure this information is somewhere around the internet, but I can't find it.
I have a device that takes a DC barrel jack. I don't know the polarity it expects though. There is a marking though. ...
3
votes
2answers
110 views
Why are the power transmission/distribution systems AC and not DC?
Is there a good reason why we are not in the process of completely converting our electrical transmission system to DC? The main reason for using AC on the grid (no offense Tesla, I love you man) was ...
1
vote
3answers
107 views
How is current lowered as Voltage is increased in AC power transmission
I was reading about power transmission on wikipedia and came across the explanation of the efficiency of AC power transmission that said power in the load = (I^2)* R while power transmitted= IV. The ...
4
votes
1answer
73 views
2 full bridge with 2 secondary winding in series… is it possible?
simulate this circuit – Schematic created using CircuitLab
Is this possible? Think of the center tap transformer as a 2 winding connected in series
7
votes
2answers
1k views
Can Arduino Mega handle 6 motors independently
I wonder if anyone can help me
I am modifying an ROV and thinking of using Arduino Mega
I am new to electronics and robotics and wonder if the Arduino Mega can control 6 DC motors independently as ...
1
vote
1answer
55 views
Which electro motor to use for steering a kite? (guestimation marathon)
I'm doing a pet project in which I want to fly a kite from my computer. For this to happen my plan is to build a little box hanging under the kite which includes a raspberry pi (connected to my laptop ...
2
votes
1answer
148 views
Mixing AC and DC power in a circuit
This is likely a noob question, apologies if the answer is obvious.
I'm trying to control a furnace using a 3.3V microcontroller. The furnace operates by connecting a common 21V AC "hot" line to one ...
5
votes
2answers
167 views
Should I use multiple voltage regulators?
I have five devices that need to be powered. I would like to use one DC source to power the four devices. Should I use voltage dividers, voltage regulators or a mixture of both? Also, any ...
0
votes
2answers
573 views
Why does my laptop charger beep?
My laptop charger is a 110-220V AC to 18.5V DC. Of late, or maybe I just heard it now, it makes a beeping noise. The noise is very very low. I have to put my ear to it to hear it.
The charger works ...
2
votes
3answers
108 views
DC-DC isolation for my car stereo… Where do I start?
I recently noticed that my jeep's stereo whines with a frequency that seems proportional to the rpm of my engine (and alternator), and is louder when my headlights are on.
If my stereo was powered ...
2
votes
2answers
397 views
AC/DC Adapter for Camera Flash Mod
I'm trying to modify a Nikon SB-26 camera flash to use AC power instead of batteries. I have a setup similar to this with two dummy batteries connected to wires that lead out of the battery housing. ...
2
votes
1answer
153 views
(How) can I run a microcontroller and DC motor from the same battery?
I have a microcontroller (a PIC10F200) that I'm using to control a DC motor. It's a very simple circuit. A button is pushed and the pic sends output for certain increments of time. The thought is to ...
13
votes
10answers
2k views
Ways to determine polarity (dc) without a meter
I came across this question about how to figure out the polarity of a cell phone charger without a meter. This made me think of what methods you could use to figure out the polarity other than using a ...
2
votes
1answer
123 views
Common DC ground with two bridge rectifiers
I have an old AC transformer with many taps off it at different voltages. Connecting a voltmeter to tap 2 and tap 3 gives 25V and connecting it to 3 and 4 gives 5V. I connected them to two bridge ...
8
votes
7answers
19k views
What happens if I connect two different DC voltage sources in parallel?
I have a computer power supply that I'm hacking together as a bench supply. For this particular model to power on, I need a minimum load across both +5V and +12V.
"Easy," I thought, "I'll just ...
0
votes
4answers
890 views
dc level shifter
I am a high school student. Please help me, i want shift a 24 volts at the input to 6v on the output!! i need a dc level shifter but i dont know its contents!!
1
vote
1answer
122 views
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 ...
2
votes
1answer
165 views
advice on a transformer for power-supply
i know this type of question is common and yes i could just buy a known transformer for $10 on ebay or something. either way :)
i am interested in building my own power supply, something variable ...
0
votes
3answers
154 views
Lower Voltage of 15 VDC Power Supply to 13 VDC for DC Blower
I have a centrifugal blower, model 007-A42-32D, that uses 12 VDC at 17.5 amps. The performance information provided by the manufacturer, SPAL Automotive, was acquired at 13 VDC.
I have a power supply ...
1
vote
2answers
67 views
Will a device capable of receiving a 200 Vrms input signal happily accept a 200 VDC signal?
To the best of my knowledge, Vrms is used to express an AC signal as the equivalent DC signal that would produce the same power dissipated in a resistor R; I believe this is best calculated using a ...
0
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1answer
88 views
Can someone explain impedance in simplest way? [duplicate]
I know in DC it is Resistance of the load.
In AC is it impedance of a line correct? can someone please help me understand impedance and types of impedance.
Zero Sequence, Positive sequence and 2 ...
3
votes
1answer
139 views
Why does this insulator separate two conductors with equal voltages?
Here goes a view-from-below picture of a 3 kilovolts DC railway catenary
Here B is a suspension cable, C is a two-stranded contact wire - one which the train pantograph touches. Between B and C ...
2
votes
4answers
472 views
Protect DC Circuit from too much voltage
How do I protect a 3v DC circuit from being damaged if someone accidentally plugs in a 12v power supply? The circuit will draw much less than 1 amp.
