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Questions tagged [voltage]

Voltage, otherwise known as electrical potential difference (denoted ∆V and measured in volts) is the difference in electric potential between two points (adapted from Wikipedia). Voltage can be constant (DC) or varying (AC).

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Determining suitable wire gauge for LED-strips (voltage drop)

I am software engineer by trade and a novice in this field, please point out any mistakes in my assumptions and vocabulary regarding this topic. I am designing a lighting plan based around commonly ...
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Voltage increase by connecting Voltmeter

I've got this scheme. V1 and V2 are voltmeters without their own power supply. (V1 gets power from the measured circuit, V2 is powered separately, but in this case from the same power supply.) The ...
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Mistake in published paper about magnetic levitation?

As I was reading through this paper: Nonlinear Model & Controller Design for Magnetic Levitation System, I stumbled cross section 3.3 which I could not follow. Summarizing section 3.3 Non Linear ...
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484 views

Convert [-24V,24V] range analog signal to [0V,3.3V] range for ADC

I need to realize a circuit that converts an analog signal from [-24V,24V] to [0V,3.3V] before sending that signal to an ADC "MCP3208". I found the circuit in the picture below and it works perfectly ...
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Voltage Translator (74HC4050) Voltage Fluctuations

I have a simple circuit with a simple problem that I just can not fix. I have a 74HC4050D hooked up to an SD card. I have a 0.1uf on the 5V line and 2.2uf on the 3.3V line. Whenever a signal is sent ...
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PSpice VSIN frequency - how to set it in rad/s?

I know, that if I want to set FREQ, I need to set it in Hz, not in rad/s. I know, that 1 Hz = 2*pi rad/s, but how to do this in PSpice? What should I enter exactly? and btw. if I want to set VOFF (...
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Why the opposite of the passive sign convention is not the active sign convention?

Studying the fundamentals of circuit theory, I was reading the Wikipedia article on the Passive Sign Convention and found out about the Active Sign Convention (ASC). After searching many introductory ...
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Why do I have voltage on Collector and Emitter when NPN transistor turns on? How to get rid of it?

I have a 2N3904 NPN transistor. I'm feeding the base 5V. the transistor turns on just fine and it shorts the collector and emitter. However, when I turn my meter on volts, I read around 1- 1.5 volts ...
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38 views

Calculating equivalent resistance using loop analysis with no applied voltage

I have a bridge circuit that I am supposed to find an equivalent resistance between points K and P for using loop analysis. I am aware that a delta Y transformation is the much more direct route, ...
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57 views

Linear Regulator Operation

I have a linear regulator with three pins. It's identifier is LM7805. I've taken a look at it's datasheet and it looks unlike linear regulators I've encountered. Is the the op amp circuit included in ...
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Producing clean power with multiple switch mode power supplies

Thanks, I am new to using this site, I apologize for my vague post earlier. Here is a schematic I been working on. The project requirements are 5VDC, and 20VDC. The 5VDC is to power the ...
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Voltage drop on power bench supply for channel being off

If I measure voltage drop between terminals of my bench power supply (spec) I get -15 mV when channel output is turned off. Why it is not reading 0? I believe it's due to internal impedance of the ...
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How to go about finding the transfer function of a non-linear circuit?

Note: The concept of Transfer Function is only defined for linear time invariant systems. Nonlinear system models rather stick to time domain descriptions as nonlinear differential equations rather ...
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Off load voltage in npn transistor as a switch

There is transistor tutorial on sparkfun.com (https://learn.sparkfun.com/tutorials/transistors/all). I am wondering why there is 1.3 V drop depicted across the LED1 on the picture, since when the base ...
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35 views

Source voltage of circuit with diodes when output voltage is given

Tried solving this using KVL, and solving to get the currents for the different parts of the circuit, however got stuck when trying to compute the source voltage especially that I'm unsure if the ...
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Finding Current in Parallel RLC Circuit with 2 voltage sources?

I've spent sometime learning about step responses for series/parallel RLC circuits, but this problem takes things a step further, since C seems to be in parallel with a series combination of RL and a ...
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How do you calculate average absolute value of a sum of sin functions with different amplitudes and frequencies?

I cant seem to find the answer anywhere. I remember there was a simple formula for doing this but I dont have the book with it anymore. Finding where the function is positive and where is negative and ...
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141 views

RL Circuit Analysis with 2 sources, how to find current of resistor?

I've been tackling some problems related to natural and step responses for RL & RC circuits, but I think I've hit a major roadblock for this RL circuit. I'm trying to find the time constant and ...
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48 views

How do we get the negative voltage input value of this Op-Amp?

This is an exercise we did in class about the linear limitations of an Op-Amp, I get how we get the conductance and the Current value. But I don't understand in this KVL how did we get the value of $$...
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79 views

Resistor for buzzer current consumption limiting calculation

I would like to know how did the circuit designer of the circuit in the image calculated resistor R100 value. My guess is that the 100ohm resistor is to limit the current to ~20mA. I have tried to ...
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62 views

Safety of the input

I have been shocked by a faulty piece of equipement (valve preamp) about 3 years ago. This kind of equipement use lethal voltage to run the valves (450VDC is common). I want to protect myself ...
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Voltage wrong reading for ph_ph

I measured ph-ph voltage (l1-l2) equals 100 v, (l1-l3) & (l2-l3) equals 55 v. However, when I measured ph_n equals 55 v for the 3 phases. I tried to measure earthing but all neutral points all ...
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84 views

How to calculate the output voltage of the mirror circuit?

Please refer the following circuit added. Output voltage (Vout-A) is measured as follows, Following is the way I have started analysis: Krichhoff's voltage law around the loop ( R12 -> R3 -> V_BE(Q2)...
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201 views

Driving a voltage boost circuit with a piezo driver circuit

For a university project, I'm creating my own small speaker. This speaker includes a speaker driver circuit consisting of a transistor and 3 resistors (see figure below). simulate this circuit –...
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How does the size of a conductor affect a driven voltage?

I'm designing a capacitive sensor which uses an active shield to focus the sensing field. This much works well. Now, in order to most effectively protect the active signal from noise I'd like the ...
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63 views

Voltage drops after connecting two batteries in parallel

I have two batteries 12V GEL 130Ah, each charged to 14.4V. After connecting them together in parallel, the voltage drops gradually and equalizes at 12.99V. (I use 10mm^2 short cables to connect them ...
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How to get NodeMCU to detect an external switch closure of an unknown voltage?

I'm getting really into home automation as a side project of mine and one of the next things I would love to automate is my doorbell. Short question: If I have a switch (momentary button in the form ...
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101 views

Is ripple voltage is too high?

I'm trying to calculate voltage ripples on bulk capacitors of my guitar amp. Here's a schematic of it: simulate this circuit – Schematic created using CircuitLab According to formula Vpp=I/fC, ...
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34 views

finding two drain currents

below I have the following problem along with the circuit's picture My analysis is as follows: for G and D open \begin{equation} I_{D1}=I_{D2}\hspace{10mm}therefore\hspace{10mm}V_{ov1}=\:V_{ov2} \...
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71 views

LC circuit with switches

I am confused with the above problem. I tried but I am not sure that my answer is correct. Please verify my solution for any conceptual mistake.
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96 views

USB Voltage auto selector (Prioritise VUSB)

I'm trying to design a auto voltage selector circuit to prioritise USB voltage when the USB is plugged in. The power goes through some voltage regulators which then powers a MCU (ATMEGA32U). I have ...
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58 views

Independently scaling the max/min readings of an analog sensor?

I'm currently working on a project that entails reading an analog signal with an AVR microcontroller and using it to control the brightness of some string LEDs. The signal is generated by a ...
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Need fast and exact voltage follower or divider cascade

Intro: I'm designing a makeshift oscilloscope and now need an input cascade for it (it is more fun project for me, rather than industrial-grade tool). The matter is I want to get something faster ...
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104 views

What will be the output ripple current per capacitor buck regulator?

I have a existing buck regulator design. Converter part number: TPS54340Q1. Input voltage = 5 V. Output voltage = 3.3 V RMS ripple current is calculated as = 108 mA. (Don't worry too much about ...
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145 views

high voltage multiplexer for battery cell monitoring

I'm working on a battery management solution with 50.4V battery (36 cells in series with 1.4V a single cell voltage) for automotive application. i'm planning on using multiplexer and differential ...
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186 views

Capacitor to reduce initial voltage drop when starting winch?

I have a solar panel charge controller with a load terminal that disconnects when the battery (12V car battery) goes below a certain voltage (9V). I have connected a winch which draws a maximum of 15A ...
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Noise Power Spectral Density

So, I'm a physics student who threw himself into an electronics class with very little experience with circuits, amplifiers, and the like. So, please forgive me if my question is trivial or is totally ...
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115 views

How to drop high voltage DC with resistors only

Last year I made an electronics device that would drop high voltages DC to 24VDC from 50VDC, 75VDC and, 120VDC. These voltages drops were selected by using a 3 position, 12 terminal, no 0 position ...
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341 views

How to control l298n voltage output

Recently I've been working on an RC car controlled by a Raspberry pi mounted on an RC car and connected to 2 motors via l298n dual h-bridge and im using a 12V battery to power the l298N However it ...
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63 views

Induced Voltage calculation in rotating conductor

I have uploaded the example problem and the solution of it. A positive charge will face force Q(vXB) in -z direction which will lead to separation of charges. The separated charges create an ...
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314 views

Can UPDI Enabled AVRs be Programmed at 1.8V?

Microchip's new line of Tiny AVRs use the new UPDI programming interface. After looking at the datasheets for the ATtiny817/1617, the Atmel ICE interface document, and the internet, it's still ...
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99 views

Source voltage and capacitance

Does changing the source voltage (i.e. voltage of the battery) affect how long it takes for a capacitor to charge in a circuit? Am I right in saying that since the capacitor charges until it reaches ...
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How to make a open-circuit cable fault detector?

There are projects like this one over here: Underground Cable Fault Distance Finder, which checks if a given line is short-ciruited with any of the other lines. The location of the fault is also ...
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Problem with Simulation Results VS Tested Results for a signal

For the circuit shown i am having some trouble wondering why my tested signal looks like this (i understand that it could be clipping) but when i measure my circuit in the simulation it is correct? ...
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192 views

Zero Cross TRIAC circuit for regulator fails on voltage spike

I am using a ZC TRIAC circuit to switch and regulate an electric appliance e.g. a table fan, a electric drill etc. I must confirm that proper SNUBBER circuit is used and everything works fine. I ...
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101 views

Why does the potential difference in a quartz crystal change?

Please help me out here... If the potential difference at a mid-point between two opposite charges of the same magnitude "Q" is = 0V.. then how does the potential difference in a quartz crystal change,...
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Why does introducing this circuit in cause a higher voltage in existing circuit?

I have a Trans Control circuit that under normal conditions sends a 5V signal to a 9 ohm solenoid. The TCU controls this solenoid. I have parallel wired a manually activated 5V supply that I activate ...
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87 views

Low voltage LED bulb or jump into line voltage?

I'm not even sure if this is appropriate StackExchanage community for this but I wasn't sure where else this sort of question would fit. So I tinker with electronics here and there and primarily it ...
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230 views

Voltage across capacitor in a electrical circuit (LCC circuit)

My networkanalyses book told me that the voltage across the capacitor C2 is given by: $$\text{U}_{\text{C}_2}\left(t\right)=\text{U}_{\text{in}}\left(t\right)+\text{C}_1\cdot\text{L}\cdot\text{U}_{\...
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133 views

Xbee TX pin voltage wrong when booting with UART connected

I'm interfacing an XBee PRO 900 HP with a Beaglebone Black using UART5 on the BB. I'm using the 5v interface board from Adafruit (XBee Adapter kit - v1.1) I'm have been having intermittent problems ...