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# 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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3k views

### What is the physical meaning of 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 ...
35k views

41 views

### LtSpice antisymmetric sine pulse

I am trying to create a pulse voltage source in ltspice. The pulse should look like a half cycle of a sine wave however the rise and fall times should be different. I can create such pulse with the ...
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 ...
212 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 + ...
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 (...
826 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 ...
192 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 ...
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
353 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 ...
182 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 ...
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 ...
445 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 ...
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 ...
1k 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 ...
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 ...
168 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 ...
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: ...
401 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 ...
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 ...
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-...
251 views

### Voltage of Different Voltage Sources in Parallel with Diodes

I am working on a project in which I will have two different power sources, which I will have to dynamically switch between to supply power to devices. These two power sources will likely be similar ...
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 ...
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 ...
56 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. ...
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 ? ...
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 ...
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. ...
284 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 ...
12k 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 ...
69 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 ...
108 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:       &...
88 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 ...
440 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 ...
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 ...
57 views

### Physical connection of AC and DC voltage sources in series

in many circuits (Amplifiers, Filters etc) at the input terminal I saw a sinusoidal voltage together with a DC term, i.e. a voltage like v(t) = sin(wt) + 1 [V]. We may imagine that this signal is ...
145 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 ...
131 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 ...
77 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. ...
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-...
621 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 ...
109 views

### Why is usage of a current source preferable over a voltage source for charging capacitor?

I came upon this sentence in a paper concerned with dielectric elastomer actuators (DEA): Due to the capacitive behavior of a DE, a converter with current source functionality should, therefore, ...
60 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 ...