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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Voltage help with resistor

Im using a 3.7V 18650 Li-ion battery (Ultrafire) and the circuit calls for a 27 ohm resistor. But one battery tested at 4V and the other 3.7V. Is the resistor too low now? Which rating should my ...
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1answer
75 views

Check if Voltage is in a certain range

I did not really found anything on google to accomplish my idea, so try here to find out an answer: My task is defined as follows: I need to check if the input voltage is in a specific range. Lets ...
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1answer
84 views

Other ways to vary voltage besides PWM

I am trying to control an electronic throttle, the ECU (Pi Innavo M220) I am currently running allows for PWM, but several other components are already drawing a lot of power. The M220 Has digital and ...
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1answer
17 views

Power Metal Oxide Resistor - Maximum pulse voltage

I am looking for a suitable series resistor (220k) for a 230VAC optocoupler input. The device must meet requirements from EN60664-1. I am still trying to understand the final requirements, but from ...
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2answers
73 views

I require a more comprehensive explanation of the function of zener diodes

I would first like to establish that I am simply the most basic of beginners in the realm of electrical engineering, and that complex terminology will only cause me to ask more questions. A circuit ...
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1answer
75 views

Fundamental questions about capacitors? [on hold]

I have read several chapters in several textbooks, watched several in-depth tutorials, etc. There are still somethings that were either not explained clearly enough for me, or not explained at all. ...
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1answer
84 views

What would happen to voltage if I connect an extremely long cable to one battery terminal?

Suppose I had a 9 volt battery and decided to connect an extremely long cable to one of the battery terminals as show in the picture below: Assuming that we waited enough time for thing to settle ...
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1answer
52 views

What is the difference between voltage UNBALANCE and voltage IMBALANCE?

I'm a Brazilian (so not a native English speaker) who just came across the user guide of a power quality analyser which has, among its features, measurement of both "voltage unbalance" as well as ...
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1answer
51 views

X-rated capacitors required for DC input voltage circuits

In my project I am using 12V DC from external power supply and EUT will load max 2A; in which I am using EMI EMC filter. I have considered Input MOV’s for common mode and differential modes, ...
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1answer
32 views

Voltage in the phasor domain

Given the below circuit (at regime) I have to calculate the voltage \$v_u(t)\$, by knowing that. \$I_0=3\$ mA, \$I_s(t)=I_m sin(2\pi f t)\$, \$I_m=2\$ mA, \$f=1\$ kHz, \$R=1 \$k\$\Omega\$, \$C=100\$ ...
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4answers
200 views

Zener diode voltage too low

I'm trying to regulate 12V to 4.7V with a zener diode. (I'm doing this to protect an AVR's gpio pin, so the current is very low.) I tried the simplest circuit with the zener, but it does not work as ...
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1answer
45 views

how to store low voltage in capacitor [on hold]

Sir,i am not electrical eng so i want to ask, which capacitor can be used to store very low voltage say 0.1 voltage 50 micro ampere,also please write farad value,i've searched the net but did not get ...
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4answers
918 views

Does current flow on an open transmission line?

Please take a moment to look at the diagram below: The question is if the lightbulb will momentarily flash when the switch is closed. I think it will but I get the feeling I am wrong. The reason ...
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1answer
61 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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votes
2answers
333 views

Will 0.16 amp rated fan replace a 0.3 amp fan?

I have a noisy PSU fan (400 watt Coolermaster PSU), It's 120mm and 12 volts. I have found an identical fan which is also 12v, but rated 0.16A, as opposed to the original 0.30A fan. I'm aware PSU ...
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3answers
39 views

Question about Z-Diode circuit and measurement

I am currently diving in in embedded development using ATMega Microprocessesors. I have now a question regarding Z-Diodes. My circuit is powered by a 9V battery that gets through an IC7805, thus ...
3
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1answer
73 views

Is a device with high voltage and low current safer than a device with low voltage but high current should you accidently bump into the +/- pins?

For example, my lead acid car battery is rated at 12 V/700 A, whereas my switch mode power supply has 250 V/6.3 A. If I were to accidentally bump into the +/- pins of either battery (forming a full ...
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1answer
30 views

Capacitor Varying Charging Voltage

I was wondering what would happen if you took a 2.7v super-cap and began to charge it with 2.5V then while continuing to charge it the input voltage drops to 1V. Also what would happen the other way ...
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0answers
36 views

How do I create GPIO outputs from circuit to connect to Arduino Micro

how do i design the GPIO outputs so i can connect it to two pins on my Arduino and get the readings. ie. if green didoe is on GPIO 1 = High, other wise Low if red diode is on GPIO 2 = High, ...
2
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1answer
32 views

What are the technical specifications of Tesla “cell level fuses” one fuse per cell

How do Telsa cell level fuses work? Can they protect against short circuits and internal cell fusing? How is the current distributed throughout so many fuses? A total of 200 amps could pass through ...
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1answer
26 views

Current/Voltage sensing for wheelchair battery using arduino

I am working on a project that requires me to monitor the power consumption of wheelchairs across a spectrum of different activities. (electric wheelchairs batteries are 2x12V) To do that I am going ...
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1answer
25 views

Relationship between capacitance and capacitor voltage rating?

I recently went to buy a capacitor of 10 microfarad and I was told by the shop that 10microfarad 67 volt is available. The confusion for me is that will I be able to charge the full 10microfarad only ...
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2answers
117 views

How electric devices can sustain at such a huge voltages? [closed]

This is a common experience.When we buy any electricity run device ,it is given with it's specifications like it's operating voltage,current ranges. Also,normally power supply is 240 V , 50 Hz. But ...
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1answer
50 views

how long will an 11w bulb last on 3 x 500mAh 3.7v cells [closed]

I have this question that I can't seem to figure out. I have an 11 Watt bulb and 3 500mAh 3.7V Lithium Polymer Cells. And the question is how long the bulb will last. Can anyone help me with the ...
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3answers
59 views

What could be the voltage of this common DC motor? [closed]

Below is the picture of a common DC motor usually used in electronic toys. This motor is quite common so I guess someone may be knowing it's voltage and how much current it draws. I could've tested it ...
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1answer
36 views

DC motor rpm change by under supplying voltage

If I have a 6V dc motor running at 20 RPM with a gearbox already attached and I only supply the motor with 5V from a cellphone charger what will my new rpm be?
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1answer
89 views

Unexpected sinusoidal wave at low voltage setting on oscilloscope?

I'm fairly new to electronics in general, and I'm learning to use an oscilloscope. I have a 10X probe attached to a 1uF capacitor that is completely discharged. When I set the time interval on the ...
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1answer
78 views

Current flow on Load (A)

simulate this circuit – Schematic created using CircuitLab From my analysis, and applying circuit theory, I find that Load(A) will have current flowing equal to 0.1Amps due to the PS, and ...
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0answers
24 views

Angles of phase displacement between phase and line voltages in star connected transformer

I recently did a lab in class which required using an oscilloscope to measure the phase difference between the line and phase voltage of a star to star connected three phase transformer. Two of the of ...
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2answers
50 views

Changing a 24volts module device to 12 volts supply?

I have a 24 volts requirement to power a relay module device. I want to install it in car but the car has available 12 volts from the main battery. Temporarily, i have added a device to step up the 12 ...
2
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1answer
118 views

Current, Voltage, and Power Sensing for 115 V AC Circuits

I am trying to sense voltage, current, and power with an Arduino (Due) for monitoring and diagnostic applications. To get reasonably good input (better than Kill-A-Watt), I have designed an AC sensing ...
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2answers
81 views

Why is inductor completely canceling out current?

I used this calculator to determine that my hand-turned inductor has an inductance of approx. .5 uH. simulate this circuit – Schematic created using CircuitLab When I measure this ...
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1answer
65 views

Possible to run nichrome at very low voltage?

I want to operate a 1-inch length of nichrome 80 wire, 26 gauge, at 200-600 degrees Farenheit. This type of wire has 2.657 Ohms of resistance per foot. So, for 1", there would be 0.22 Ohms of ...
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1answer
39 views

DC Op-Amp Output at an unexpected voltage?

For some reason Op-Amps are impossible for me. I'm experimenting with them a little bit. I have the following circuit... simulate this circuit – Schematic created using CircuitLab This ...
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6answers
156 views

A doubt on potential difference

This is a schematic diagram of the circuit. Is it possible to take the voltage difference between AB as E? I have learned that the potential difference in parallel circuits are the same, ...
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2answers
92 views

Voltage drop through a resistor using Ohm's Law?

I'm having a very hard time comprehending basic Ohm's Law. I was recently watching a video on the operation and use of Operational Amplifiers, and was completely lost because I couldn't understand ...
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0answers
65 views

TS317 voltage regulator 12v to 3v

I'm building a Star Wars Millennium Falcon and happened that I need 12V to my LED strips and I need 3V to each of my single LEDs; And also to my smoke machine that runs at 3V. I went to the Maplin ...
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1answer
65 views

How to determine potential difference of a point on a circuit relative to another point?

I know this is a simple question for many of you. But still I am a beginner in this field.So I hope it is vital to know about this. Okay let's assume we have a circuit like below. In this circuit ...
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0answers
26 views

How to calculate data in PSS/E and export it to Excel?

I am using an IEEE 39 bus system for my purpose about load shedding. I want to calculate some data after disturbance like voltage(PU), the rate of change of frequency, Ymatrix, inertia_constants(H), ...
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1answer
52 views

Triangle Wave Generation

What would be the best way to generate a triangle wave that can operate at 250kHz @ 4V peak-to-peak? I have tried the following circuit: However, the best I could obtain was a 4mV peak to peak ...
2
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1answer
32 views

How do I model an LED with SPICE WITHOUT access to a Manufacturer's Datasheet

Looking to create a model of an LED (RL5-WW15030 from Superbrightleds.com): ...
1
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1answer
65 views

AC-DC Adapter - Output lower than rating and what's this 'cont' output for?

I have a Canon AC adapter, Model K30321, that I'd like to use in a project. I'm attempting to test the adapter for correct voltage output. Adapter specs: ...
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2answers
104 views

Why use ground in oscilloscopes and what's the difference between it and a volte meter?

I am a high school student And we lately started studying rc and rl circuits And my questions are What is the difference between volte meter and the scope? Why we use the ground as reference in the ...
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2answers
85 views

Why is my body the path of least resistance during a shock? [duplicate]

I must say that electricity is hard to grasp conceptually. Just when it makes sense, you think hard about it and it all becomes confusing. When someone says electricity takes the path of least ...
0
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1answer
66 views

Voltage Drop Between Battery and Load

Why is the total length of wire in a circuit used to find the voltage drop between a battery and a load? Suppose the load is a distance l away from the battery. Wouldn't the voltage drop between the ...
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2answers
52 views

Estimate minimum discharge voltage in a laptop battery

The objective is to determine the best 18650 cells to replace the ones in my laptop battery. To do that, I need to know the minimum voltage the battery controller accepts before ordering the OS to ...
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1answer
26 views

HSPICE code to cut off supply voltage of a subcircuit

I am trying to cut off the supply voltage "Vcontrol" of a subblock "circuit" for a very short time using a pmos, a nmos transitor and a voltage source. The Hspice code is as follows: ...
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1answer
62 views

Driving 3V chips from 3V3 chips and vice versa

Are there going to be any problems mixing logic levels derived from chips driven by those different voltages? My initial view is "no" because of the 300mV clamping diode drops, but just checking other ...
2
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4answers
573 views

Higher voltage or more amps?

Im planning on building a E-Bike and have made some calculations and only need my 190rpm/V brushless motor to spin around 600 rpm to give me a good speed. So by this calculation I only need to ...
0
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1answer
58 views

Charging Capacitor with Solar Panel

I have a 2.7V 100F super-capacitor. I am going to be charging it with a 6V 1W solar panel. Now the solar panel only puts out 6V when it is receiving the best sunlight so this means the output from the ...