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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55 views

How to power several gate drivers with as few power supplies as possible?

I am designing a 3-phase three-level NPC converter (same type as: https://trinhquocnam.files.wordpress.com/2015/12/t-npc.png?w=767&h=434). The box this converter will be placed into is fed with ...
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2answers
245 views

Phase voltage from unbalancd line voltages symmetrical components

I'm trying to calculate the phase voltage of a given unbalanced sources star connected from the given line voltages. I'm trying to employ symmetrical component synthesis to find a solution. I know ...
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3answers
314 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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251 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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796 views

GND of 9V batteries in a circuit

I have a very simple question. I'm building a circuit that uses some integrated circuits, some of them need 5V and GND, and some like opamps need symmetrical power supply. In summary, I will need 3 ...
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2answers
400 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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39 views

How do I determine this node voltage?

I'm wondering why the node voltage of C will equal to Vc = Vd + 770 I've done research but have no clue. Any help will be appreciated.
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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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74 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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1answer
52 views

DC power filter curicut

I have a problem in powering my wireless Panasonic landline telephone. It works on 9v power with a transformer that work on 220v and gives as output 9v and it works fine with this way. I try to power ...
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2answers
436 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 ...
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3answers
806 views

How to apply nodal analysis when value of dependent voltage source depends on current of a plain wire?

Need to find out the value of V11 (V11 = 4*I9 Volt), as it's a dependent source and it's value is depending on the current through the plain wire W9 of no resistance. I solved this with Mesh current ...
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5answers
250 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
2k views

How to run 5v relay on 9v?

I have a 5v(coil) dpdt relay. Running it with 9v is safe or not? How can i reduce the voltage from 9v to 5v ? How much resistor i need ?(i do no want to use voltage regulator pls)
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1answer
316 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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278 views

Can you measure the voltage produced in the heart using an oscilloscope or multimeter

Can you measure a PQRST wave using a multimeter or oscilloscope, it you can will two leads be enough and why are 12 leads standard tor ECG monitoring?
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463 views

Simplest way of getting +/-12V from a 0-12V power supply

This question is probably easy, but as a total electrican noob I couldn't really find a suitable answer so far. Some circuits, like amplifiers, require a -12V and a +12V rail respect to the ground. ...
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2answers
1k views

Supernode with 2 voltage sources and 1 current source: node voltage analysis

I'm struggling with defining a super node in this case. My initial thought was to create a super node with V1 and V2, but I'm not sure how to handle the current source. Doing KCL in this configuration ...
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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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1answer
325 views

Does an Ideal voltage source with current flow from negative terminal absorb power?

I had a question during a physics tutorial today and it has left me quite confused. One of the questions was to find the power delivered by the 6V source. I figured that P=VI, I is negative with ...
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2answers
694 views

5/12V voltage TTL selector

I want to select an output of 5 or 12 V with an isolated digital output control signal (Vcc 3.3V in the picture, 0 selects 5V, 1 selects 12V). Right now I have something like this: Corrected version: ...
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1answer
177 views

why add a resistor parallel to voltage source? [duplicate]

Sometimes I see a resistor parallel to voltage source (such as image below), isn't it completely useless ? Edit: I see the other similar question now, but I think it doesn't have the right keyword ...
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1answer
606 views

Short circuiting voltage source

I was working on a problem for finding the thevinin equivalent circuit. In order to find the short circuit current , I short circuited the terminals across which I had to find the thevinin impedance. ...
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57 views

parallel rlc voltage source

I am learning about circuits and I have some questions regarding circuit initial condition: - no initial energy stored before switch is closed - there is current at L1 at t = 0- I am wondering: ...
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2answers
243 views

ADC EVAL_AD7984_PMDZ voltage source and signal source sharing common ground

EDIT: (problem definition shortened into 2 sentences) For anyone using EVAL_AD7984_PMDZ and having troubles to apply -2.5, 0, 7.5 [V] and signal to differential probes, because the voltage source and ...
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1answer
2k views

Nodal analysis with voltage source

Good evening. I was attempting to do a node analysis on the circuit above when I ran into a problem. Assuming I have my reference node at the bottom below the 2 ohm resistor I come up with my ...
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2answers
156 views

Voltage regulator 5v 1.5A

I have voltage source of 7v 250mA. Question is, when I apply it to regulator do I get 5v and 1.5A on the output of regulator?Or do I need 1.5A for a linear regulator ? How much current would I need ...
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2answers
63 views

The role of internal voltage source resistance in pulsed operation

I have a question regarding the role of the internal voltage source resistance in pulsed vs DC operation. Here is a sketch of the situation I imagine: simulate this circuit – Schematic created ...
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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 (...
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3answers
239 views

High current voltage reference from a small current constant reference and regulator

Say I need a high current voltage reference. A very accurate and low noise part is available, but can only supply 10mA and happens to be expensive. So multiples of this part cannot be used. What if we ...
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1answer
701 views

Short circuit protection for my voltage source

Can someone suggest me some short circuit protection schematic? I have 12V DC source (1.2A max. output current) and I will use it in some amateur electronics projects, but I would like to add some ...
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1answer
53 views

Current analysis with 2 voltage sources

I am not able to solve this question , I initially thought that in order to find the current of this series circuit it would be Vtotal / RTotal , however I am not getting the correct answer with this ...
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3answers
323 views

voltage\current sources

I read in a book that image-1 is not a valid connection since you apply on the same two terminals a and b different voltages however image -2 is said to be a valid connection and I don't understand ...
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1answer
70 views

As a voltage source voltage increases, how does the internal resistance increase?

As title says, supposes that maximum voltage of AC voltage source, or just voltage of DC voltage source, increases, because voltage source equipment is changed. What happens to internal resistance of ...
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1answer
243 views

Current clamp circuit after buffer amplifier

I'm building a voltage supply that uses a DAC to convert a binary string into an analog voltage. The DAC can't source a lot of current, so I'm using unity-gain amplifiers after the DAC output on each ...
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2answers
97 views

Combining a benchtop power supplies

So I made an error when purchasing a power supply that was far below desired voltage (dc). The power supply I bought certainly produced enough current, however, and I am wondering if it is possible to ...
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1answer
787 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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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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2answers
360 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
193 views

Treat valve heater as resistive or constant current?

I want to run a 13V(300mA) valve filament from a 6,3VAC transformer, using a voltage doubler(Greinacher circuit). I am using PSUD2 to simulate the circuit, Which gives me 2 options for the load, ...
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1answer
209 views

RC Circuit with a non-ideal switch

We can find a lot of material regarding the charging of a capacitor. For example http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capchg.html and many more It is just an ideal RC circuit. The ...
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1answer
3k views

“Voltage source is shorted” simulation error

Take a look at the image below, Why is that bottom voltage source is shorted? (http://everycircuit.com/app/) give me the response as voltage source is shorted, why is that? As far as I know, If an ...
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1answer
688 views

Direction of resulting I through simple circuit with 2 voltage sources separated by 2 resistors in series?

I'm wondering how to find out which way the resultant current flows when you've got a really simple circuit with two voltage sources separated by 2 resistors in series. See the below circuit (the ...
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1answer
220 views

Voltage drop across a series with a source and a resistor

I've tried using KVL and KCL but nothing I do is resulting in an answer. I am struggling with how to treat the voltage drop and the two resistors that are in parallel with each other. I think I may be ...
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2answers
593 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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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 ...
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2answers
32k 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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2answers
8k views

How can I convert a cordless trimmer to a corded trimmer? [closed]

I have a cordless hair trimmer that I would like to turn into a corded unit. Its AC/DC charging adapter outputs 3V at 1000mA, while the trimmer's original battery is a 2.4V 600mAh NiCd AA unit. ...
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1answer
264 views

NPN switch: What is wrong with this circuit?

I'm trying to use a single source for both output and an NPN switch (5V - 2Amp). I cannot get higher than 500mA at the output, with VLoad about 4.3 V max. simulate this circuit – Schematic ...
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6answers
888 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, ...