# 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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488 views

### Convert Current source to Voltage source in Laplace domain

Is it possible, once I've converted the circuit diagram into its Laplace equivalent, to replace a current source which is in parallel with, in this case, a resistor and inductor by the usual V=IR ...
51 views

### Back up 9V battery when circuit is unplugged from AC

I have to work on a circuit that basically goes like this. I have two voltage sources, a 9V battery and AC. The AC is the main source, however, when this is unplugged, the 9V battery must come to the ...
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 ...
32 views

### Incompatible association

I know that operational amplifiers have a stage in which there is an incompatible association (VCCS + VCVS). How do I show that this configuration gives an infinite gain? I am considering general two ...
53 views

### current in resistor in series with voltage and current sources?

What would be the current in the 3 ohm resistor next to 45v source? Im not sure if it should be 45/3 or 5 amps!
74 views

### 6VDC power sources for momentary switch

I recently asked this question where I'm trying to wire up this momentary switch to my Raspberry Pi 1 Model A such that: The switch is normally open; and When pushed down: it closes the circuit, ...
340 views

### current dependent voltage source problem

Hey, I am studying dependent sources.as an exercise i am trying to solve the circuit in the image. i have been banging my head against the wall on this problem and i really want some help. please. I ...
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 ...
235 views

### Dependent or independent sources of voltage and current

I am confused with this term of dependent and independent . What exactly this mean .does dependent sources mean that if we connect a dependent source of voltage and current in same circuit ,they will ...
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 ...
273 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 ...
351 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 ...
265 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 ...
896 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 ...
436 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 ...
41 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.
6k 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 ...
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. ...
55 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 ...
444 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 ...
858 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 ...
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 ...
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)
399 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 ...
300 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?
481 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. ...
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 ...
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 ...
355 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 ...
741 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: ...
190 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 ...
672 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. ...
58 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: ...
255 views

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 ...
3k 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 ...
157 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 ...
64 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 ...
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 (...
243 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 ...
742 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 ...
55 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 ...
331 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 ...
73 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 ...
264 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 ...
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 ...
825 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 ...
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 ...
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-...