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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High Voltage and Low Charge - Analogy (ESD & Lightning)

How can something have high voltage but low charge? Can anyone provide an analogy for this? I was going through the ESD topics and read the ESD events usually have high voltage but have low charge? ...
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WS2812b interference and bootup behavior

TL;DR: how can a slowly rising power supply voltage on an arduino crash the WS2812bs connected to it? How can I protect a signal wire even better from electrical interference? This my question in a ...
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Voltage Across a Resistor CircuitLab

I have this circuit in CircuitLab, and I need to get the actual voltage across VR. To do this, what expression would I need to enter in my simulation?
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Why is the voltage divider formula used in this circuit to find the terminal voltage

I'm going through the book Practical Electronics for Inventors and there is a chapter about voltage sources that talk about practical voltage sources. It calculates ...
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How to determine what battery to use?

I am making a project that requires two different voltage levels, 5V and 12V (although this can be lowered to 7V minimum). I have two voltage regulators as described by the schematics below: I want ...
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138 views

Removing voltage spikes and overshoots using power MOSFET as switch and 555 timer as pulse generator

I'm trying to turn on a power LED using LM555 timer as input signal of IRF630N N-channel power MOSFET as Fig1. Fig1. pulse generator and switching circuit. Here is the output of LM555 Timer (Not ...
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Why won't my USB powered LED remain on until after the 3rd attempt to turn it on?

I have a USB powered LED that I use for late night desk work. It's 8" long overall, housed in a bendy kind of stem with the last 1.5" being the light. It looks like a Popsicle stick that doubles in ...
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57 views

Switch between 2 voltage dividers depending on input voltage

I have a power managent IC that has features of Under and Over Voltage Protection through the EN and OVP pins. These pins are enabled by manipulating the voltages on the pin via a 3 resistor voltage ...
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AC phase current sensing using Isolated delta-sigma modulator

I am trying to design a isolated AC current sensor. I've chosen the AMC1106 Isolated Delta-Sigma Modulator. (change my mind if you think there is a better solution for 220V AC; 2A Max; 0.25%) The ...
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How do I drive a 5W low-pressure mercury UVC bulb?

How do I determine the voltage and necessary power supply for this bulb? This bulb is a UVC low-pressure mercury vapor bulb used in my air purifier. It fits in a G23 Socket; normally I would expect a ...
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Same voltage inverter

Is there any reason for not finding an inverter that only converts from DC to AC maintaining the same output voltage, e.g. a 220V DC to 220V AC inverter?
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The solution for current

I am trying to solve this problem but I failed to solve it. Please can someone solve it for me?
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Use a power bank instead of batteries for a LEGO train

I'm tired of charging and charging batteries for my LEGO train. It takes 6 AAA batteries. I have several questions: 6xAAA means the motor needs 9V, right? When using rechargeables they only supply ...
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Regulated Power Supply

I am supposed to simulate this circuit (regulated power supply 5V), however I am not understanding what's the point of the resistor R. Is it a load resistor? Cause i thought these needed to be before ...
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How to prevent current and voltage fluctuations for loads connected in parallel to the same power supply?

I have a 12V dc power supply/battery supplying a class D audio amplifier, 12V dc linear actuator (controlled by raspberry pi through an h-bridge), LCD screen and LED light strip (Lighting intensity ...
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247 views

Will lower voltage power source supplement/charge higher voltage power source?

I would like to add a 4.5V 1.5W solar panel to supplement an existing electrical setup in my vehicle. My current setup is an Arduino and other electronics wired up to an "add a fuse" in the car fuse ...
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Confused with a heater electrical specs

This heater's electrical specs are given as: I guess this is a pure resistive component and the power P = Vrms^2/R. This formula tells me power is a function of the voltage and the resistor. But the ...
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What is causing a voltage drop on the 5v power rail on this bench setup?

I am testing a video card and because I need to probe the logic chips on the 5V circuit I thought about hooking it up to my bench PSU. I am powering and measuring on the ISA pins where 5V and GND are ...
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How to measure voltage drop across a wire?

I need to measure the voltage drop across a short piece of wire (about .25 to .30 inches long). The wire (a fusible link) is permanently attached to a battery which is permanently connected to a ...
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1answer
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12 V DC Li battery voltage regulation question

I recently bought a 12 V 50 Ah Li battery with the intent to use it for a 12 V DC trolling motor for a boat. The trolling motor runs at up to 30 A. I have read that lithium batteries tend to output ...
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Why does current only choose path of least resistance sometimes

Say we have the following setup simulate this circuit – Schematic created using CircuitLab Input is pulled high and current flows through it as long as the switch is open. As soon as it closes ...
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Ramp up and ramp down for solenoid valve [closed]

I'm trying to activate a solenoid with a linear ramp in voltage of 0 - 12 VDC in 200 ms. The load current of solenoid valve is 1 amp. An RC series circuit helps achieve a soft start but in an ...
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1answer
125 views

Where does the 1V voltage come from?

I have a four PLC with many digital I/O connected similarly to the schematic below. If I use multi meter and measure the voltage between the two points in the schematic, why is it showing 1V? Isn't it ...
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LCD backlight LED voltage. Insignia (Sharp) Model NS-32D20SNA14

I have a TV LED back light panel from Insignia (Sharp) Model NS-32D20SNA14 I have isolated the back frame with the LED panel. The power clip is intact. Everything else is removed. Using a VOM to get ...
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MOSFET Gate driver - negative voltage with Zener circuit

I was reading about minimizing MOSFET switching loss when I came across an article by Texas Instrument on how to use negative voltage, instead of ground, to faster discharge MOSFET gate capacitance. ...
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Shunt resistor to measure voltage on the load resistance

I have to answer this question but I can't do it at all. Can somebody help me, please? The question is: "There is current control on the feature. Let the bus works on batteries with nominal voltage ...
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How is voltage always able to increase, if electrons move at the speed of light?

If current is the rate of flow of electrons past a point. Let's say a wire is full of electrons, and of course they pretty much are already going the speed of light, minus friction. What would ...
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Push-Button Voltage Spike (not debouncing)

I have a circuit which reads push-button presses. If it is pressed, it turns on the door by rotating motor. In this system, safety and stability are keys. I added r/c filter to debounce button and ...
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Why is my IC giving abnormally small voltage outputs?

I just got some new battery holders, with 4.5V and 6V respectively. I hooked up the 4.5V holder to a SR latch IC, and while it did hold a state, the LED was abnormally dim, despite having no resistors ...
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Why is it working, and can it cause damage? [closed]

I have a dab radio the requires a power source of DC 7.5V 2A However an AC adaptor that out puts 5.0V 2A is powering the radio and it functions fine Why is it working and can it cause damage ?
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Circuit Analysis with constant current and voltage sources

This is a homework question of sorts. I am supposed to find the voltage across AB. I know that the answer is 24 volts by traversing from B to D to C to A adding up voltages of resistors, but should I ...
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What does a mobile battery percentage indicate? [closed]

Just curious to understand, what does a mobile battery percentage indicate? What is the input and output in the percentage formula with respect to batteries?
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Relationship between power angle and real and apparent in ECO dataset

I am trying to parse the ECO dataset, which includes 1-second electric data collected from residential houses. Link to dataset: http://vs.inf.ethz.ch/res/show.html?what=eco-data But the relationship ...
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why is the the Line voltage drop formula is \$\Delta V=2I_1 (Rcos\theta+Xsin\theta)\$,not \$\Delta V=2I_1(\sqrt{R^2+X^2})\$?

There is a single-phase two-wire system,if the resistor \$(R)\$ of line is 1Ω and the reactance \$(X)\$ of line is 2Ω,and the power factor is \$\theta\$ .The Line voltage drop formula should be $$\...
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Could a modified sine wave inverter destroy/damage the AC adapter for a laptop?

I recently encountered a scenario where I attempted to use a Energizer EN500 modified sine wave inverter to provide power to a Dell 180 watt AC adapter. The circuit powering the inverter was 12 volt, ...
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What is the voltage value measured by an 8-bit ADC chip showing a binary reading of 64? the reference voltage is 3.3V

I followed the explanation in this post. I did 3.3 V/256 = ‭‭0.01289 V . I also did 3.3 V/(256/1.5) = ‭0.01964 . And lastly, I used this formula: I just keep getting the wrong answer! Please could ...
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How to build a 18650 battery pack without a spot welder?

I'm building an autonomous boat (which needs to get me a bottle of fine whisky from Scotland) for which I want to build a battery pack. The boat is currently powered by a cheap Li-ion battery pack, ...
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68 views

6.2 V zener shows lower voltage (Multisim)

I have this circuit with a 1N4735A 6.2 V zener diode. I am trying to figure out why am I measuring 5.1 V across it. The circuit is a transformerless power supply with more or less 60 mA of maximum ...
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Why are flat copper cables with holes used for high voltage ground?

I saw that a flat copper cable was used for the ground connection in a high voltage lab. I was wondering whats the difference as opposed to a normal cable ?
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Read triangular wave with positive and negative part to Arduino

I generate a triangular wave with a 555, and I want the Arduino to read this signal. What should I do to read negative part?
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How to calculate snubber value for triac

I want to use an optocoupler and triac to control a ceiling fan. How do I calculate the snubber resistor and capacitor value? Will the inductive load of the fan change my snubber value?
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How to increase current while keeping the voltage the same?

I currently have an Arduino Uno board which has an output of around 5V @ 900mA. Is it possible to bump up the current to around 3-4A while keeping the voltage the same? Maybe with a transistor, but I ...
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Why am I reading 22VDC / 69VAC when measuring between myself touching a MacBook and ground?

If I put the positive probe of my multimeter on earth, and touch the negative probe with my hand, while another hand is touching the metal surface of my MacBook, I get around 22VDC or 69VAC. I cannot ...
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Why can we use less voltage drop to transmit the power if the higher voltage is used?

In power distribution systems, a given amount of power can be transmitted with less voltage drop if a higher voltage is used. However,i don't understand the reason about this In my thinking,if i ...
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130 views

18v vs 12v battery question

I have a few 12v LED lights that run off cigarette adapters. I wanted to be able to use my 18v drill batteries so I pulled the guts out of an old charger and added a cigarette socket. The lights work ...
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USB-C PD, Voltage and Current of Power Adaptors [closed]

I have a rather basic question... but I don't want to take chances. I have two MacBook Pros, one which ships with a 87W power unit, and the other a 96W power unit. Now, I understand that a device ...
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161 views

How to use Arduino to control the switch on a 4.5v circuit

I've been building a wall mounted lightsaber using the below board. At the moment the switch is turning it on and off, however I want to automate this with an Arduino. Can I use a digital output ...
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High voltage capacitor, in a low voltage system?

Quick question: is using a capacitor rated for high voltage (let's say 35V) in a system that let's say supplies 5V (like for LEDs or what have you) dangerous? Since it can store up to 35V, will it ...
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Can I use a plug rated for a DC circuit in a low voltage AC circuit?

I have an spare 2-conductor plug rated for 12VDC at 5A from an old project. I’m now working on a Class II low voltage (24VAC) projet for which I need just such a plug. Is the plug rated for the DC ...
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What could happen if I touch a constant current source for example 5 Volts 1 Amp..?

Yes, I am talking about a constant current source not a voltage source. Would the 1 Amp go to my body?

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