What is Dc circuit: Definition and 105 Discussions

Hi guys: I like physics but i have many questions concerning electricity and magnetism. 1- Do we accelerate electrons when increasing the voltage in a DC circuit. 2-What does it mean when we say there is a potential difference across the plates of the capacitor. 3- What is the potential and...

Thermoelectric generator induce DC current and I just wants to understand how can a transformer step up DC. If there is something else please make me clear.

Homework Statement http://postimg.org/image/8oweasluj/ Each rectangle in the figures represents a resistor with resistance=2.9kΩ. a) What is the net resistance of the circuit of Fig 1 connected to the battery? Each resistance has R=2.9 kΩ. b) What is the current flowing into the...

Homework Statement http://puu.sh/7gYwk.png Consider the circuit shown above. Find the current Ia flowing through the resistor and the power for each element in the circuit. Which elements are absorbing power? Homework Equations P = V x I = I^2 x R = V^2 / R The Attempt at a...

Hi everyone, first post. Just wanted to say I've been using parts of this forum for a long time for help in understanding all kinds of concepts, and have found it immensely helpful over the years. Thank you for all of your contributions! So, here goes with my hopefully very simple question...

Hello guys, My teacher gave me a question regarding calculation of equivalent resistance, trying to solve which I'm losing my sanity. I feel a bit ashamed because this is my first post and I'm using it to ask a doubt, a little selfish of me. But it's kind of urgent so I don't really have a...

I've been able to get all of the problems up to this point, but I have never seen a problem like this before, so here it goes: 9. Below is shown a simple resistive current source. The resistive load is represented by a 10 kΩ potentiometer. What is the current through the resistive load over...

My choice of solid state Dc circuit breaker is the Mosfet, easily available( i got loads!) i want the mosfet to interrupt the circuit to protect the load from overvoltages This is what I've done so far, please help its not working the way i want it to. note to mods: i also put this...

My choice of solid state Dc circuit breaker is the Mosfet, easily available( i got loads!) i want the mosfet to interrupt the circuit to protect the load from overvoltages This is what I've done so far, please help its not working the way i want it to. the resistor connected to the...

Homework Statement http://imgur.com/9fk2QXV Homework Equations V=IR The Attempt at a Solution I am stuck on part d, i have found the answers for part c to be 12,6 and 8 for I1,I2, and I3 respectively. For part d they seem to say that I3 is just equal to I1+I2, but i am confused...

I have attached the picture of the circuit. I'm trying to figure out the steady state voltages across the 2 resistors and the capacitor. V_s is given to be 10V DC. At steady state in a DC circuit, a capacitor acts as an open. When that happens, we shouldn't expect any current to flow...

Hello. I am new to electronics and physics. Since injuring my back at work, I now have a lot of time on my hands to learn about the things that facinate me. So please forgive me for any wrong terminology or spelling and grammar mistakes. I have recently made a small jacobs ladder using a lm555...

Homework Statement Need to establish a Thevenin equivalent for the circuit attached. Homework Equations None given. Need to use Kirchhoff. The Attempt at a Solution I worked out the following: I said that R3 and R4 are in series as there is no current splitting because 0A...

[Confuse!]Capacitor and resistor in DC circuit, please help :) Homework Statement The figure in attached file below shows a circuit in which a battery (electromotive force = 10V) is connected with three capacitors (capacitance = 1 microFarad, 2microFarad,3microFarad) and two resistors...

If I have a constant emf, then connect it to a resistor and an inductor and capacitor in parallel. At the time when the switch is closed (I haven't drawn it), the voltage across L and across C should be the same since they are in parallel(?) (in fact it should be in any time later) But...

Hey everyone, I am trying to solve for the circuit that I have attached. So I know that for a opamp, it does not draw any currents into its input side and the nodes b and c are the same potential. To figure out the potential at node b, i need to know I_6, but that 6k resistor is messing...

Given the scenario that there is only 1 DC voltage source is there a way/ circuitry that can increase the current. I know using a low resistor could induce a higher current in the circuit, but here is the trick, the resistance is fixed. Anyone who know how to do it, please do shed some light on...

Homework Statement Breakdown, and find the total resistance for this circuit. Homework Equations V=IR Parallel Circuits - 1/Rtot = 1/R1 + 1/R2 ... Series Circuits - Rtot = R1 + R2 The Attempt at a Solution http://img696.imageshack.us/img696/4176/centralkootenayj2011122.jpg...

Hello, an elementary question here. I am thinking about a BJT transistor amplifier circuit which has the usual AC coupling capacitors to allow the AC signal to pass while isolating the DC component. I understand that but my question is how is this decoupled AC signal represented on the actual...

Homework Statement While the voltage induced between the points P and Q is changing, which is the high potential end of the inductor? Explain your answer. P.S. sorry for the fail Paint job lol Homework Equations The Attempt at a Solution I know that in a DC circuit current flows from the...

https://www.physicsforums.com/attachments/39765 a) Calculate the current through the 5Ω resistance. Use '+' sign for the current directed from right to left, and '-' sign if the current flows from left to right. b) The magnitude of the potential at 'a' is? Please help me with the two...

Homework Statement Find the value of CSB(current source B) and determine the value of I. Homework Equations Mesh equations The Attempt at a Solution mesh: a -> Ia = 0 b -> 11Ib = -12 c -> 6Ic = 12 d -> 2Id = -8 e -> Ie = -CSB Ic = 2 A Id = -4 A then I cannot...

Greetings E.E. Gurus! I'm a noobie in need of your guidance! Here's the situation: I have a 5V DC, 0.25 amp (1.25W ?) power source from an oil pressure switch wire on an old truck that is activated only when the engine is running. My goal is to activate a 12V DC, 2.5 amp, 30/40W...

Need help with circuit problem---I need to convert a simple dc circuit---approx 3 v---into pulses---perhaps as rapid as nanoseconds in betw pulses---however not yet sure of freq----also dc polarity would remain the same. Is there any component or device that could act as an ultra rapid on off...

Edit: Nevermind, I figured it out! I jumped the gun in making this post. I'm doing another problem from Schaum's Outline: Basic Circuit Analysis. The problem, #3.24, and its solution are found in this...

Homework Statement From my Basic DC electronics text. 2 questions, multiple choice, but I seem to be able to talk myself into several of the options. I've combed the book thoroughly, and humbly come to you folks in sincere desperation. The resistance of an/a Inductor/Capacitor in a DC...

Homework Statement The circuit in the figure is composed of two batteries (e1 = 8 V and e2 = 6 V) and four resistors (R1 = 110 W, R2 = 40 W, R3 = 30 W, and R4 = 50 W) as shown...

Homework Statement Hello all, I just have a quick question regarding the modeling of the following circuit (see attached). I am trying to derive the equation for the voltage across the capacitor as a function of time. I come up with the correct result when the element polarities are the same...

Homework Statement For the circuit shown below, the capacitors are initially uncharged. At t=0, the switch S is closed. a) Determine the current in each resistor immediately after the switch is closed. b) Determine the current in each resistor a very long time after the switch is closed...

Homework Statement For the circuit shown below, assume that the batteries are ideal and determine the following: a) The current through each resistor, including direction. b) The potential difference across the center branch of the circuit (the one including the 8 ohm resister and 20 V...

In a DC circuit charges flow in the opposite direction to the electric field. Is the difference in potential energy over two points b and a of a point charge due to the source charge of this field defined as voltage?

I understand pretty much everything related to this, except how many currents should I put when arbitrarly putting them. The number of resistors? The number of wires? The number of loops? I'm seriously lost here, thanks!

Hi, This isn't so much of a home work problem just a request for clarification from those that are more intelligent than I. I actually just wrote the final for Basic Circuit Analysis and there was a question that left me totally stumped. I've attached a VERY crude, much less complicated...

Homework Statement Find a) the potential difference between points a and b b) the current of the 20 ohm resistor I drew the diagram in MS Paint. Should be good enough. http://img188.imageshack.us/img188/6515/circuitf.jpg 2. The attempt at a solution I just don't know where to start...

I have a quick silly question for a first-timer at assembling circuits. I have a circuit with a photodiode input and a BNC/coaxial output to a scope. The circuit diagram is below. In assembling this circuit, I'm not sure where to ground to. I've put it in a metal enclosure. One book says...

Homework Statement Is it possible to find the P.D. across the 10ohm resistor. Homework Equations Kirchoff's second law. The Attempt at a Solution Well KSL states that the sum of the pds is equal to the sum of the emfs. I(10) + 0.25(12) = 2 Gives the wrong value for...

Homework Statement See attached image for a circuit diagram. The assumptions are that transients have died out and the currents and charges have reached their equilibrium values. I have to calculate the charge on the capacitor.Homework Equations Q_C = C \Delta V V_C(t) = Q(t)/C =...

Homework Statement http://img99.imageshack.us/img99/8412/parallelcircuitsfn3.jpg http://g.imageshack.us/img99/parallelcircuitsfn3.jpg/1/ (see attempt at a solution for problem) Homework Equations none The Attempt at a Solution Are the two resistors in red parallel or would...

Homework Statement http://img144.imageshack.us/img144/9724/tricircuitxv4.jpg http://g.imageshack.us/img144/tricircuitxv4.jpg/1/ Homework Equations Re = R1 + R2 + R3 The Attempt at a Solution I don't really understand this problem. I'm not sure how to approach it. I thought 5 =...

Homework Statement Two identical light bulbs A and B are connected in series to a constant voltage source. Suppose a wire is connected across bulb B as shown (basically, the wire is connected to both ends of bulb B; light bulb A is closer to the positive side of the cell). Bulb A: 1...

Homework Statement the title says everything, any formula that to find resistance in a DC circuit of one resistor and one capacitor connect parallel, as well as the current through each of R and C (the known values are R C and V) Homework Equations seem to me i = (V/R)e^ (-e/RC), but...

A current pulse exists, in which the current jumps from 0A to 10A, stays at 10A for 200 microseconds, then drops from 10A to 0A. What makes a current pulse different from the current that runs when a switch in a DC circuit is left closed for 200 microseconds...is it the same concept?

Hey, I need to find a way to convert a pulse that can be in any amplitude from 0 to 5v and output DC voltage at the same amplitude. any ideas? :) Liad.

[b]1. Find the reading of the ammeter [b]2. I've 2 questions here: Link to the Attachement please,thx. [b]3. I had made a simplified diagram, but wasn't sure of the calculation. Help me out with a complete explanation please~! Thx so much!

Homework Statement Design a DC cct having a 15V battery to provide the following node voltages: +10V, +5V, and -5V with respect to a circuit ground node. Select your resistors such that the max power demand on the battery does not exceed 1mA. The Attempt at a Solution I made a cct with 4...

I have an amplifier circuit as shown in this picture, http://www.fileden.com/files/2006/8/19/175303/4.wmf" And I need to do a DC analysis on it to find the current into the base lead (I_B) and the voltage over the collector-emitter (V_CE). Realizing this is DC and that the capacitor will...

Homework Statement Rank the brightness of five bulbs (3 different circuits) considering all the batteries and light bulbs are identical. 1st circuit - 1 battery hooked to bulb A. 2nd circuit - 1 battery with positive end hooks to bulb B then bulb B connects to bulb C then comes back to...

I'm having difficulty to understand a circuit from my textbook (figure attached). Essentially, the currents seem to go in opposite directions and ultimately meet. It looks strange (circled area), but maybe there is a simple explanation behind it. I wish I could redraw the circuit in a simpler...

Hi Guys! well! i have made my all efforts in solving this circuit please help me. WHat technique should i use? Super mesh? or what? Plz help me

can you use a dc circuit in a transformer? will it work the same way?