Tagged Questions
1
vote
1answer
60 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 ...
-1
votes
1answer
72 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
3answers
91 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 ...
3
votes
2answers
106 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 ...
4
votes
1answer
72 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
1
vote
3answers
100 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 ...
2
votes
1answer
146 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 ...
1
vote
2answers
86 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
1answer
120 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 ...
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
votes
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 ...
1
vote
3answers
216 views
Does a resistor in an AC circuit produce the same heat as in a DC circuit?
Does a 1k ohm resistor produce the same heat in a AC circuit which has an rms voltage of 10 volts (60 hz.) as it would in a 10 volt DC circuit?
0
votes
2answers
130 views
Easiest / cheapest way to build a dc power supply in the 150VDC range
I am looking to build a power supply to power a 150 V DC armature motor that will pull a maximum of 4 A. The cheapest I have seen so far is the following on ebay.
I'm looking to build one myself but ...
1
vote
2answers
93 views
Can this ultrasonic emitter be DC driven?
The datasheet of this ultrasonic specifies that the maximum driving voltage is 10 Vrms, which suggests that it should be driven by an AC.
Is my assumption correct? ...
3
votes
3answers
330 views
Dangerous ac or dc [closed]
Is alternating current more dangerous or direct current?.
And give me explanation for that....
Assume that 230v,50hz AC voltage and 230v DC voltage,Which is more hazard to human life...?
Which has ...
1
vote
2answers
208 views
How to switch both AC and DC voltage to a load
I have a load, an electrode basically acting as a very tiny capacitance, that I want to supply a voltage or bring to ground. The voltage can be either DC, up to about mains voltage, or AC into low KHz ...
3
votes
1answer
151 views
switch small DC voltage with 90v. 30hz AC signal
I need to momentarily activate an approx. 50mA @ 24V DC load, using a 90V, 30hz AC signal line. Whatever method is used, it needs to have the smallest current draw from the signal line possible.
I ...
0
votes
3answers
201 views
Why do some power adapters output an AC voltage?
Out of most of the electronics I use, I have two, both of them speakers, that use a power adapter that simply steps down the voltage without rectifying it. Why did the designers choose to put the ...
-5
votes
1answer
113 views
DC Generator to AC Alternator Retrofit [closed]
I want to put together a proposal into retrofitting the damaged DC generator with an AC alternator, and fitting the two other working generators with AC alternators.
The diesel engine is still ...
1
vote
0answers
114 views
Control DC circuit with an AC lock switch
I am currently adding circuit with a horn and some lights powered by a motorcycle battery. The circuit should be using about 12v 18A. What I want to do is control the circuit with a lock switch. I've ...
0
votes
2answers
530 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
245 views
How can I power and dim two sets of LED lights where one requires12VAC and one 12VDC
I am building a wall unit and I would like to use some LED Tape Light (12VDC, 48ft Total 1.45W/Foot) to light the shelves. Then I'd like to use a 12VAC adjustable LED spot light (5W) for the center ...
3
votes
3answers
343 views
Why is there alternating current in my wall socket?
Why is the standard of delivering electricity to our homes is via alternating current, and not direct? As far as I know almost every electronic device has an AC»DC converter because their internals ...
1
vote
2answers
89 views
Powering a fan with an AC adapter [duplicate]
Possible Duplicate:
Choosing power supply, how to get the voltage and current ratings?
I need to power this fan which is rated at 12 V, 0.95 A, 11.4 W. I am unfortunately without a DC power ...
-3
votes
1answer
332 views
AC and DC Resistance [closed]
I have a few questions regarding my task of calculating AC and DC resistances:
If a cylindrical conductor is made of two different materials, would the conductor's effective resistance be the ...
5
votes
2answers
402 views
How does an inverter affect the computer?
I have rampant power failure in my country. So to mitigate, we have an inverter that basically converts the charge from a big lead-acid battery to AC. But as far as i know this doesn't produce pure ...
1
vote
1answer
157 views
AC / DC Backup Power Supply For Solar Irrigation Pump
I think this technology exists but I don't know what the device is that I need to do the job.
I need a DC Power supply that will pull input 110V - 220V AC (for here or international) and will output ...
3
votes
3answers
854 views
If a wire is rated 10A, 120v AC. How many amps could I put through it of 13.8v DC?
I am using a wire that is rated 10Amps at 120v ACwith a car headlight and a SLA battery. About how many amps could this wire carry before getting warm or melting of DC current at 13.8volts?
1
vote
1answer
181 views
Simple AC line state detection for digital controller input
Last year I moved into a house that has an old ('50s-'70s vintage) GE low voltage lighting control system. It uses 24VAC momentary wall switches to toggle solenoid/latch relays that feed 12 main ...
3
votes
2answers
6k views
230V AC to 5V DC converter, lossless
Is there any IC which converts 230V AC to 5V DC? As lossless as possible. I want to connect my microcontroller to an ordinary electrical socket and I don't have enough space available. Thanks.
2
votes
1answer
534 views
Advice for building a dual rail, +- 10V, regulated, DC power supply, 25mA
I am looking for some directive to build a dual rail, +-10V, regulated DC power supply to supply 25mA to two resistive loads. I am very new with this; I am an engineering student and this is my first ...
4
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
1answer
327 views
How should I isolate AC and DC on a small PCB?
I am designing a small PCB (1"x1") and it will have some DC logic traces (5V and GND) and some high frequency AC power traces (100V 1000Hz 50mA). Are there any special considerations I need to take ...
1
vote
3answers
164 views
A device that runs on AC current it's voltage inside is measured by always turning the multimeter's knob to AC voltage:same for DC right?
I've bought a cheap multimeter and it's not automatic. I've to manually rotate the knob.
I live in North America. AC current is used in my home. Does this mean I can always measure voltage by turning ...
0
votes
1answer
177 views
Solenoid Power Source
So Im trying to make a solenoid a switch, but I have heard two different ways to power it: AC or DC power source. I learned in class that an AC power source would work because a solenoid is basically ...
0
votes
0answers
66 views
Choice of an electric motor for a motorcycle [closed]
I'm new here and this seems to be the suitable place to ask for help(correct me if I am wrong).
I am planning on building a motorcycle powered by an electric motor, but I am facing a big problem : I ...
3
votes
1answer
182 views
DC motor vs AC motor weight considerations
For a given power rating, does a permanent magnet DC motor have a weight advantage over either a three phase permanent magnet synchronous machine, or vice versa? Or does it work out that they would be ...
2
votes
2answers
112 views
Is there a way to miniaturize cell-phone power adapter
Is there a way to miniaturize a cell-phone power adapter to be not bigger than 1-3 cubic centimeters? Is there a way to do so by using more expensive parts or something like that?
I'm talking about ...
2
votes
2answers
563 views
Supplying ac to a dc circuit
So a while ago, i was stumbled upon a post what will happen to the dc circuit when we supply ac to it. Lets assume the ac has the same voltage as the dc. We know that ac switches direcions so there ...
1
vote
3answers
691 views
What happens if usage current exceeds DC adapter current rating?
I have a DC adapter 5 V, 350 mA. I'm using this adapter to be fed into a 3.3 V regulator which powers up my bluetooth device and a few LEDs.
My question is: what happens if I source 300 mA from this ...
-1
votes
3answers
286 views
Use household 12 V DC adapter with RFID transponder?
Is it possible to use a common household 12 volt DC output adapter with this RFID transponder. I am a newbie but I am willing to learn. Here is a diagram of this RFID transponder system of this.
...
5
votes
3answers
846 views
How does DC transmission require several times less wire than AC?
In this YouTube video (scrolled to 5:55) there's a claim that replacing an AC high voltage transmission line with a high voltage DC transmission line allows for having seven times fewer powerlines ...
9
votes
2answers
2k views
How do the tiny AC->USB power supplies work?
The iPhone and Kindle both come with tiny power supplies that take in 120v AC and output around 5V at 0.85 to 1 amp. They seem to be too small and light to have a transformer, and generate very little ...
1
vote
2answers
579 views
What do we use to convert AC to DC current in houses
Do we use an active or passive rectifier to convert AC current to DC current, and why?
1
vote
2answers
319 views
Can AC and DC be converted and compared?
This is coming from an IT scenario;
An example server may have a power draw rating of 1.5A at 230V. When connected to a UPS and the mains power supply goes out, the UPS batteries are now providing DC ...
4
votes
1answer
583 views
AC->DC supply, how to deal with chassis ground being connected to digital ground?
I have an external triple-output AC-DC supply with the following output pinout:
On the power supply, "ground" (pin 2) is internally connected to the ground wire of the mains plug. I'll refer to it ...
3
votes
2answers
2k views
What is the formal definition of Quiescent Point?
What is Quiescent Point? Is it necessary for it to be related with any V vs I , I vs I, or any such characteristic curves intersection point?
0
votes
2answers
656 views
Connecting AC wires to a PCB
I am working on a project where I am using a microcontroller to control a 5V DC relay to control a mains device (an airconditioner).
In this circuit, I would need to connect the AC wires to my PCB ...
1
vote
1answer
483 views
Regulated DC supply - need help with calculations
I am in the process of making a regulated power supply to convert AC(220V, 60Hz) to DC(9V, 500ma). I have worked out all the calculations and would appreciate if someone could double check just to ...
