Questions tagged [voltage-source]

Anything related to voltage sources, their circuit models and their practical circuit implementations. An ideal voltage source is a two terminal device whose output is a voltage signal with a given waveform regardless of its load, i.e. irrespective of the circuit to which is connected.

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8
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2answers
33k views

Explain in layman's terms Vgs and Vgs(th) of MOSFET's

I'm trying to understand \$V_{GS}\$ of MOSFET transistor. From what I understand \$V_{GS}\$ normally stands for voltage gate to source breakdown, but other than that I lack an understanding. \$V_{GS(...
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9answers
3k views

Negative Resistance

I am a bit confused about the physical meaning of negative resistance. Mathematically, a component which has negative resistance shows a decreasing voltage across its terminal when the current inside ...
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3answers
437 views

Don't individual signal sources affect each other when using a summing amplifier?

I am studying the book Electric Circuits by Nilsson & Riedel. There I learned about "summing amplifiers" and how to derive equations by applying KCL at inverting input of the op amp. I see that ...
4
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2answers
634 views

Create circuit from current–voltage characteristic

I'm trying to create a circuit from a given current–voltage characteristic like this: I want to use ideal diodes/ideal voltage source/ideal current source So my idea was for the dotted graph the ...
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6answers
14k views

How is a current controlled voltage source different from a resistor?

A current controlled voltage source produces a voltage that is linearly proportional to a current. A resistor has the same behavior. And the gain for a CCVS is measured in ohms, which is the same ...
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6answers
895 views

Batteries in parallel vs voltage signals in parallel

From a practical point of view, when you connect two audio signals to one speaker the result is that both audio signals can be heard. That means the two voltage waves were added, correct? However, ...
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2answers
1k views

Voltage source phase shift in RC circuit

I've been doing an analysis on a particular circuit. Nothing too complicated simply a resistor and capicator in series with a 2v supply at 500Hz / 0 degrees. Essentally what im trying to understand ...
3
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1answer
211 views

DC Voltage Source - circuit problem

I'm currently trying to build a DC voltage source from an AC source to a school project. The circuit worked fine when it had no voltage regulator, as it was just a transformer + full-wave rectifier + ...
3
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1answer
2k views

How to improve load transient response of an LM317 voltage-regulator powering an audio amplifier?

I am building a voltage regulator circuit for powering a pair of mini-speakers (about 3-5W) with built in amplifier and an old mp3-player/FM radio. The power source is an old mobile phone charger (...
3
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1answer
808 views

MOSFET Drain, Source and Bulk connected to a source

Background: I have a circuit for a FGMOS and they are describing the Fowler-Nordheim Tunneling (FNT) mechanism. The picture features two transistors: the main (FG)MOS and a secondary MOS to ...
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2answers
191 views

What happens when I connect an LC circuit to only the positive terminal of a voltage source?

I have the following circuit: simulate this circuit – Schematic created using CircuitLab The switches flip at the same time. In the position shown, SW1 is causing a loop that only connects to ...
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5answers
5k views

Diode circuit with parallel voltage source

What will be voltage V if all diodes are considered ideal simulate this circuit – Schematic created using CircuitLab
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3answers
331 views

Connecting Two Analog Sources to One Analog Sink

Q: Connecting Two Analog Sources to One Analog Sink without the sources effecting one other What I want to do: I basically want to add a radio tuner/MP3 player in a car. Now, that car already has a ...
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3answers
177 views

why isn't Norton transform applicable on ideal sources?

An ideal voltage source has no resistance in series to it, so the it's transform the current source must have zero resistance in parallel to it. This means that all the current passes through the ...
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3answers
8k views

3 Watt LEDs in Series - Using constant voltage source

I have 20 x 3 Watt LEDs and have a 80W constant voltage (not constant current supply). I originally wired this up with 5 sets of series string of 4 LEDs from my 12V supply, however I have been told ...
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2answers
441 views

What should I use from given options to power a raspberry pi?

I have a system which consists of 2 12V DC motors(0.65 A on max load) and 1 RPi 2 model B. I want this system to be plug free. I have Li-Ion batteries to power up motors. I use a L298N module to drive ...
2
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3answers
7k views

why does the parallel resistors with voltage source can be ignored as well as resistors in series with current source in term of equivalent circuit?

I have a problem dealing with equivalent circuit. I don't know why when the resistors that is parallel with the voltage source can be ignore as well as one in series with current source. Of course the ...
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3answers
970 views

Paralleling power supplies for higher current

I am looking at using two Cincon (CFM80S240 and CFM60S240) power supplies in parallel to achieve a higher current output. Is this possible? If so, can I just hook them up in parallel, or is there some ...
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1answer
1k views

Special Source Transformations

I'm not sure if this was asked already, but I could not find it when I searched. We're learning about source transformations, and while reading my textbook I came across this: and in the following ...
2
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1answer
132 views

Source transformation with impedance being inductor or capacitor

I found a presentation that states the following about source transformation when the impedance is capacitive/inductive: While electrical circuits books, like Nilsson's, says: If I transform the ...
2
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1answer
60 views

Nodal analysis: how can I represent the current i2 in terms of voltage over R2?

I am doing the nodal analysis of this circuit: I have successfully wrote the current equations for node A, using nodal analysis, that I found it to be: ...
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2answers
5k views

Ideal Voltage and Current Sources in series

For the circuit below determine a) the current I, b) the voltage \$ V_R \$ and c) the voltage \$ V_o \$ across the current source Note: VR should be V subscript R and the case is the ...
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1answer
355 views

How can I do this source transformation/Reduce this circuit?

I've seen and solved many examples but I'm stuck here . Maybe I'm confused as to what is parallel and what is in series here. I can do the transformations up to the 1A current source but I can't ...
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1answer
5k views

How to convert current source to voltage source when to current sources are in parallel?

I've been given the following diagram with two current sources: I have to calculate the current shown by the ampermeter (A) which is quite easy once I'm done with the conversion. The theory says the ...
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2answers
2k views

How do I switch between primary battery and backup battery, if the primary battery drops below operating voltage or get disconnected?

I have low power system which requires dual batteries to overcome the loop holes in the current system. Currently I have two batteries: Primary Battery Li-Ion 3.7V 1800mAh and a secondary battery Li-...
2
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1answer
77 views

What are the operational differences between a battery and a plug-in voltage supply?

I have a neat little circuit with which I am powering an electromagnet. Below is the schematic for the PCB I created. The positive lead of the electromagnet is connected to 12vdc and the negative lead ...
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1answer
2k views

LT Spice and inductors parallel to AC voltage sources?

This is a circuit I designed in LT Spice. There is no transformer component in LT Spice so I specified L1 and L2 as magnetically coupled with K L1 L2 1 when I try ...
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0answers
51 views

Alternative to battery powered isolated voltage source [closed]

For some nano-physics related measurements, a very clean low-noise bias current is required. People mostly use a battery powered isolated voltage source along with a big resistance similar to this. ...
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6answers
2k views

Is there any physical device called current source?

I have seen both current source and voltage source in many electrical circuits (in paper). When it comes real hardware battery can be considered as a voltage source. Then what is a current source ? ...
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5answers
4k views

Ohm's law of a circuit which has both a voltage source and current source

The voltage source has a specific voltage through it regardless of the circuit's current and its resistance while the current source has a specific current through it regardless of the voltage through ...
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3answers
10k views

Do batteries (voltage sources) supply constant voltage?

I know that voltage sources are those that can supply constant voltage. The producing current may vary with the load. Suppose I have a rechargeable battery. I fully charged it and started using it. ...
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5answers
262 views

Why would I need a low-dropout regulator?

I am creating a device utilizing multiple components, all of which have an acceptable operaating voltage of about 5 V. One component has an operating voltage of about 6 V. I am looking at relevant ...
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3answers
11k views

LTspice dependent voltage sources circuit

I am trying to add dependent voltage sources in LTSpice, but I need to make a voltage dependent source whose voltage depends on the average of two voltages. How can I build that in LTspice? The ...
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2answers
63 views

Select between two sources with transistors

I'm sorry if this has been asked before but I can't find useful data on this matter. I have two sources of data and I want to select one of them using transistors. If I had to guess I'd make the ...
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2answers
102 views

Combining two ideal voltage sources with an impedance between them

Solving a problem, I came across the following source transformation:        My question is: I know that I can do the following:       &...
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2answers
86 views

How much current and voltage should be flowing back into my battery?

I am very new to electrical engineering, and one thing that has been bugging me is short circuits. Main question: When I have a circuit, how much current and voltage should be flowing back to my ...
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2answers
421 views

Build a voltage-controlled voltage source out of discrete components

I'm in a bit of a pickle. I need to build a voltage-controlled voltage source, but I don't have any opamps (or time to order them). I have been working for several hours trying to simulate a circuit ...
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3answers
2k views

Problem about superposition theorem [duplicate]

For the circuit given below the voltage across the resistor is definitely 5V. If we add more than two sources the voltage will remain same as before. If we try to analyze the circuit with ...
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2answers
139 views

Is it possible to reduce the resistance of a voltage source (coil)? If yes, how can I do that? [closed]

First, I should inform you that I am a mechanical engineer, so this is an adventure to me. What can sound as basic to you, is like a new discovery for me. Second, I would like to introduce you the ...
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4answers
130 views

Connecting an LED to a “incompatible” voltage source

I'm band new to electricity and electronics and am confused by something I saw with a recent video that explains how to connect a battery, LED and resistor together. In that article (see link for ...
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1answer
75 views

Help Identifying a Voltage Regulator 0 - 5 Volt?

So this voltage regulator came from a variable resistor for my 06 Infinity QX56 AC blower motor. I have already replaced the unit with a new one but figured I would try to fix this and have a spare. ...
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2answers
361 views

Are op amp and voltage current converter same

I am trying to create a constant current output for my project between 0 - 10 mA. I read we can convert voltage to current by using op amp http://www.allaboutcircuits.com/textbook/semiconductors/chpt-...
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2answers
600 views

Why is the voltage across a dependent voltage source connected to an open circuit not zero?

I have the circuit shown below. I need to find the Thevenin voltage for it. If the dependent voltage source was a resistor instead, I think I could have disregarded it when using KVL (since the ...
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1answer
58 views

Understanding some mistakes, when trying to find the Thevenin equivalent

I was asked to find the Thevenin-Norton equivelant, and I got stuck on some things that I can't quite understand. I don't know if i need to be more specific. What's wrong with the following? And why ...
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1answer
363 views

What will happen if a dependent voltage source in parallel with a dependent current source?

What will happen if a dependent voltage source in parallel with a dependent current source. like dependent voltage source: 4Vx and current source 3Ix in parallel.
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3answers
261 views

Can I use a transimpedance amplifier using current through a resistor?

I'm designing a lab exercise for 1st year circuits students. They learn about current controlled voltage sources, but we never show them one. I know that transimpedance amplifiers are used for this ...
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1answer
12k views

Is there a difference between “voltage supply” and “power supply”? [duplicate]

A device, circuit, actuator or chemical structure which outputs a fixed voltage level is usually called with one of the following terms. Voltage Source Voltage Supply Power Supply Is there any ...
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1answer
2k views

Nodal Analysis of a circuit with a dependent source

simulate this circuit – Schematic created using CircuitLab Hi, So the trouble I am having with this problem is that I don't know how to do nodal analysis with the dependent source. I would ...
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1answer
67 views

Calculating current in one branch of circuit

I want to calculate the current labeled in the diagram \$i\$. I am thinking that since there is 3V it would be as straightforward as \$\frac{3V}{6\Omega}\$ for the current in that branch labeled. Is ...
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1answer
27 views

variable regulation source

I am learning electronics and I want to make a , variable regulation source for a soldering iron, which works at 50W, how much voltage and amps should have the output? For the soldering iron works ...