# 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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49 views

### Tellegen's Theorem Question

In Irwin's textbook on Basic Circuit Analysis, there is the following exercise: Up to this point in the book, the concepts of dependent and independent sources have been discussed, and also the ...
14 views

### How to calculate the Norton equivalent circuit for a bipolar current source? [closed]

Can anyone help me to find the impedance of the Norton equivalent circuit of this circuit? In such a way that the Norton equivalent circuit looks like this: Any help would be greatly appreciated!
160 views

### Multiple voltage sources connected to Attiny85

I have a circuit with a Attiny85 micro controller that is powered by a solar cell and a capacitor (10F 3V8). When I want to change the code on the micro controller I have to attache a USB programmer ...
52 views

### What's the voltage between series of voltage source and current source?

I'm confused with the voltage between point a and point b. Did the Vab only depend on the voltage source or i should consider the current source to sum it up?
81 views

### Spice pulsing sine source

I've been trying to create a voltage source in Pspice with a 'pulsing' sine wave. I can't seem to get it working, I've tried inputting a sin function in a VPWL source. An example of a waveform I try ...
1 vote
111 views

### DAC-driven Variable Voltage Power Supply using MOSFETs

I'm trying to achieve a variable voltage supply where the voltage can be tuned by a DAC. The DAC is limited to ~3.3 V, but the design goal for the resulting voltage supply is V_out between 0 and 15 V ...
223 views

### How does one know that the current is flowing downwards through the $8 \ \Omega$ resistor?

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 1.7 Problem Solving gives the following example: Example 1.10 ...
1 vote
88 views

### Why is the polarity of the $3 \ \text{V}$ source necessary to calculate the current flowing through the $8 \ \Omega$ resistor?

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 1.7 Problem Solving gives the following example: Example 1.10 ...
93 views

### Understanding the reasoning behind these power calculations involving voltage and current sources in circuits

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 1.6 Circuit Elements gives the following example and practice ...
87 views

### Trade-offs for generating two DC voltages for a circuit--what did I miss?

Finally getting back to my LED-lit house number sign project. Here's a block diagram of the system: I keep flip-flopping between which voltage to power the electronics inside the sign: 3.3VDC or ...
133 views

### Noise on DC voltage LTspice

Is there a way to add noise to a DC voltage source in LTspice? I'm trying to simulate a DC/DC converter and want to know how the circuit responds to a ripple/noise on the input. I.e. +/-100mV noise/...
67 views

### 480VAC to 230VAC AC AC conversion

I want to drive a single phase motor (230V, 260mA) on a 480VAC (phase to phase) source. I made this simple circuit using a 2uF, 600V AC capacitor, simulated it, tested practically and it is working as ...
1 vote
44 views

### Can I create a b-source in a statement instead of using a graphical element in LT Spice?

I currently do this, a lot in LT Spice: Is there an alternative way to write an equation and have it end up in a node in LT spice and not use a graphical element, I would like to put it in one or two ...
134 views

### If a voltage source is current limited does this actually mean that the voltage across the load is limited?

For the past while I've been struggling to wrap my head around electricity. One thing that has puzzled me to no end is the relationship between current and voltage. On paper it's a really simple ...
1 vote
73 views

### Are there optoisolators available that output a photovoltage of at least 2-3 V?

For another circuit idea, I need several cheap simple isolated voltage sources to generate at least 2..3 VDC and a couple of µA. I was thinking of a blue LED in photovoltaic mode. Are such pieces ...
68 views

### Output resistance in negative feedback

I was studying negative feedback in voltage amplifiers. I found this on Wikipedia for calculating input resistance as shown below. Following the similar method, I tried to calculate the output ...
84 views

### Using emitter follower as voltage source [closed]

I have an open-drain IC and I need to connect it to another device, avr, which is 3.3V, additionally information leds are needed. Avr should read digital signal from that open-drain device. Avr is ...
71 views

### Solution to unknown function 'v' for a voltage source in LTspice?

I have been getting this strange error. Has anyone else experienced this kind of error beforein LTspice?
121 views

### Why is Vs 36 Volts?

Stumped by this seemingly simple circuit. Why is the voltage across the current source 36 volts and not 24 volts? Please explain step by step if possible, thanks. (I solved it with an MIT circuit ...
1 vote
290 views

### Need design best practice: microcontroller controlled, variable, DC voltage source [closed]

I need guidance on designing a Variable DC power supply with the following characteristics: Microcontroller controlled DC output ~ 1V - 30V Current handling: ~5 amperes Power handling: ~50 watts I ...
1 vote
56 views

### How are this voltage source and resistor (separated from each other by a capacitor) re-imagined as a resistive voltage source?

I'm trying to implement a wave digital filter from this research paper: Emulation of Operational Amplifiers and Diodes in Audio Distortion Circuits R. C. D. de Paiva, S. D Angelo, J. Pakarinen, and V. ...
51 views

### Can batteries connected in series be treated as separate voltage sources?

I'm working on a project where one module will run on 6V and another on max 5V. As voltage source, I use 4xAA batteries (so 6V in total). My initial idea was to use a zener diode to limit the voltage ...
391 views

### Finding load current in a circuit with voltage dependent voltage source

This question has been rolled back to the version that doesn't invalidate the answers (edit by Andy aka) I'm currently studying for my Circuit Analysis class, the teacher shared some questions and ...
109 views

### Understanding thermoelectric generator and Ohm's law

I understand the simple terms of U = R * I in the context of a constant voltage - which is approximately the case for most consumer electronics, where the ...
107 views

### Is it possible to run a 3ph 220/440V motor on a standard 120/240V home circuit? [closed]

I have only basic knowledge in electronics and am looking for advice. I have the opportunity to get a really good deal on a Band Saw, a Jet J8203K. A manual for this saw can be found here http://...
71 views

### Replacing two ideal with two linear voltage sources

I am currently learning how ideal sources may be replaced with linear sources to make the application of other circuit theory possible. Unfortunately, I don't understand how the following conversion ...
49 views

### How to connect a voltage and current source?

I'm currently trying to figure out a circuit design to connect a voltage source with a current source. More specifically, I have a power supply that has a safety current loop that is wired to an E-...
662 views

### How to drop voltage to 4 volt from 5 volt source voltage with resistors? [duplicate]

A SIM800L module needs voltage between 3.7V to 4.2V. The Arduino power source output is 5 volts which will damage the module. Is 220ohm enough? I was testing with a multimeter. Its drops to 4 volt ...
77 views

### Power source switching circuit with load as a voltage source

I want to design a power source switcher for Raspberry Pi Zero. Computer has to be powered from Li-Ion battery when no USB is connected and disconnect the bettery immediately when USB voltage is ...
1 vote
460 views

### LTspice voltage source with varying Ton / Tperiod

I'm trying to simulate a buck-boost converter where Vin and Vout are constantly changing. As a result, the time it takes to charge/discharge the inductor varies as well, and a voltage source that ...
1 vote
188 views

### Trying to better understand voltage and current sources

I feel like I am going a little crazy here because the more and more I read about these things the less I understand them. So I understand that an ideal voltage source has no output impedance, no ...
171 views

### Constant voltage source for unkown load

I am designing a circuit for maintaining constant voltage for an unknown load and measuring current through R5. Following is image for reference: I had done some simulations on Tina before making the ... 1 vote
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### I have found the Rth=10 ohms, However i can't find the thevenin's voltage(between a &b)

*I converted the wye network into a delta and found the equivalent resistances in parallel and series and got it to be 10 ohms. However i am stuck at trying to find Vth. I tried applying mesh analysis ...
960 views

### I don't understand current source, voltage source, infinite resistance, zero resistance etc

When I google things like voltage source and current source they talk about things like maintaining a particular level, having infinite output resistance, or zero output resistance, etc. I don't ...
252 views

### Can power outlet be taken as a current source?

Consider a situation where I have a power outlet and I am completely unaware of the internal circuits and the fact that the electricity comes from an ac voltage source supplied by some company. I just ...
303 views

### Thevenin Equivalent Circuit of Ideal Independent Current Source

This is dual to <Norton Equivalent Circuit of Ideal Independent Voltage Source>. I have wrote it to answer a problem <click here> but I need to make it independent which requires ...
294 views

### Norton Equivalent Circuit of Ideal Independent Voltage source

For some purpose I need to derive the equivalent Norton circuit of an ideal independent voltage source. I found that it is impossible to do it. I describe the way I found it below and need comments, ...
93 views

### Problems regarding KCL & KVL

Question: Below figure represents an approximate equivalent circuit of a field effect transistor amplifier. Using KCL find the output voltage $v_2$ in terms of input voltage $v_1$. My try: I ...
1 vote
845 views

### Why is the voltage drop created by a current source added?

A few days ago a similar question was asked for the simple circuit below consisting of three elements in series (voltage source, resistor and current source). Despite professional explanations, the OP ...
70 views

### Combine voltage sources [closed]

I have a Baldor DG6E generator. It must produce 120V/240V but I bought it and it has three wires as outlets - every one produces 120V. I want to combine two wires to produce 240V. How can I combine ...
1 vote
121 views

### Does decoupling capacitors try to charge the fluctuating source back?

In common examples of decoupling capacitors, the scenario is like this: When the voltage fluctuates below or above its ideal value, capacitor either stores or releases energy to compensate the ...
482 views

### Calculating magnitude of current provided by a voltage source

simulate this circuit – Schematic created using CircuitLab A couple of days ago I attended an exam where I was asked to calculate Voltage at node A; Voltage at node B; Current provided by the ...
29 views

### Flow of current inside source

Does current flow in/inside an ideal AC voltage source/generator like it flows in an ideal electrochemical battery? How does the process happen?
79 views

### Current flowing inside voltage source or battery

Current is the flow of charges (many say electrons). Do these charges flow just between the terminals of the source/battery (terminal to terminal) ? Or These charges flow through/inside the source/...
151 views

### Power supplied by voltage source at non-inverting op-amp input

Take this differential amplifier: Where Vout is proportional to (V2-V1). Both op-amps are ideal with linear output. How to determine the power supplied by input voltage sources? Power should be P = V*...
1 vote
60 views

### finding the current in a branch with resistor, capactor and a voltage source

I'm solving a question in Linear circuit analysis 2 class. the question is to analyze a switching circuit with inductors and capacitors. this is the circuit in the time interval drawn in S-domain ...
81 views

### Very simple AC voltage question

How to simplify these two voltage sources (same frequency) into one so I can calculate the current then the power absorbed by each element
101 views

### Why is the current for $i(t)$ $5mA$, not $5e^{-\frac{t}{0.8m}}$ mA?

Close the switch of the circuit, and it is in the steady state. We open the switch at $t=t_1$ suddenly. What is the value of $i(t_1)$? simulate this circuit – Schematic created using ...