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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32 views

Does a switched on power socket consume electricity?

Lets say I have a TV and a power socket but the TV switch is off however the socket switch is switched on, so will it consume electricity?
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20 views

AC, diode & capacitor PD question

Initially 240V rms mains voltage is connected between terminals A and B in the circuit above. You can assume that the capacitors and diodes are appropriately rated to work at this voltage. When the ...
0
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2answers
39 views

Portable phone/device charger

I am doing my best to make a portable charger. Here is the link with the schematic of the circuit I am working on:Voltage regulator question .I was told that the 9 V battery I was using didn't have ...
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46 views

capacitor charge balance technique [on hold]

In buck converter only inductor current changes and capacitor voltage remains same in capacitor charge balance to achieve optimal dynamic response for buck converter undergoing rapid load change how ...
2
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2answers
201 views

Why would you use a non-contact voltage detector if you have a multimeter?

I was reading this Fluke multimeter safety manual and I came across this sentence: ...
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0answers
40 views

At what voltage do ceramic chip capacitors actually fail?

I have a circuit which uses a couple of ceramic chip capacitors (1uF, 0805, rated at 100V). What voltage would they likely fail at? In other words, what is the typical degree of overvoltage they ...
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1answer
24 views

Find the 'Effective Voltage' with only the surface under and above the 't' axis

To find the 'Effective Voltage' and the 'Average Voltage' of a voltage over time we have the following functions: $$V_{eff}=\sqrt{\frac{1}{T}\int_{0}^{T} f(t)^2 \text{d}t}$$ ...
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3answers
76 views

How does charging a phone battery work?

For example, if a phone comes with a charger rated at 5V and 0.7A, when it's plugged in to charge, what dictates the current the phone draws, is it the resistance of the phone? If I = V/R, do phones ...
4
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4answers
834 views

Voltage drop across LED in open circuit

I've searched the forums but can't find an answer for my issue. I've got a simple LED circuit powered by 5V DC. When the switch is closed, I've got 2.8V across the resistor, 2.2V across the LED, and ...
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1answer
74 views
+50

How to calculate the induced voltage?

From the given diagram: Conductor(C) is the only movable part with given velocity (v), connected to a stationary terminals(top & bottom) and an exterior circuit with a load. Will current flow ...
0
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0answers
29 views

Ups or voltage stabalizer ? What isbest in this situation? [on hold]

I damaged my macbook charger due to power surge or drop maybe not sure when switching to and off power from home generator To prevent it in future can i use a ups with the charger to prevent such a ...
0
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1answer
46 views

Controling the Voltage of alternator

I want to design a circuit to control the output voltage generated by car alternator in a way that it shouldn't allow voltage to exceed 15V and also when the output voltage of alternator is less than ...
1
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2answers
58 views

3.3v from 5v Arduino digital pin

I have an ESP8266 that I've got connected to my arduino and communicating quite well with... Now I'm looking at options to run my conifig via battery, so need to find ways to shutdown the ESP8266. ...
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2answers
116 views

In general, what does the negative voltage or positive voltage represents? [closed]

whether the negative or positive voltage represents the direction of the current flow?
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1answer
57 views

why discharging capacitor voltage in a rc circuit is positive? why it should not be negative?

During discharging, the direction of the current is opposite to the original current direction(source current).so the current is negative. likewise the discharging voltage direction is also opposite ...
0
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1answer
52 views

voltage drop & resistivity calculation

I wanted to implement below formula into excel sheet. can someone suggest me with example. cable equation example : system voltage =12v, sys current=8A, length in feet=50. Resistance = resistivity* ...
0
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0answers
26 views

Dc electrical cable calculation [duplicate]

I wanted to implement below equation in to excel sheet. Please let me know how can i calculate the below equations. Cable online Can you explain in brief. Its bit confusing with equation. Just help ...
0
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2answers
125 views

How to plan my LED circuit, voltage, and resistor

The LED emitters in my outdoor lamps blew out and I need to replace them but I have to rebuild the emitter from scratch because replacement parts are not available. The whole lamp was made in China. ...
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1answer
38 views

Gradually increase and decrease voltage on this circuit

I am using this circuit for a model lift up and down functionality. Vin is +12V. The output voltage is controlled by the 10K linear potentiometer that varies the final output from 3V to 12V. The ...
0
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2answers
39 views

Low voltage drop transistor for Arduino

I am using a MQ135 gas sensor in my project. It takes a max of 200ma and I have connected the Arduino to a battery so I can disable it when needed to save battery. I am using a transistor for that but ...
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2answers
231 views

What conditions could be expected to occur if one or both inputs of an op amp are left floating?

Question 1: Can an op amp work with both of the inputs floating? I assume that due to the input offset voltage if both the inputs are floating, the output would be +Vsat/-Vsat. Am I wrong? Question ...
3
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1answer
63 views

Can a power supply still provide a voltage if it is broken? [closed]

I have an ATX power supply that I'm trying to use, but it doesn't seem to power my computer. The power supply turns on and the fans run and I also checked all the voltages, which are correct. However, ...
1
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3answers
418 views

Voltage dropping capacitor doesn't work?

I connected a voltage dropping capacitor in series with 220v AC supply and I measured the output voltage and it was 220 v too. I was expecting to get a voltage that is less than 220 volts. Did I make ...
2
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2answers
87 views

Using a 12v switch in 120v circuit

Can I use a 12vdc switch rated at 16A on a 120vac that only use 0.5A-1A? I have a similar switch, that is 120v rated at 10A, but it's a little too small. doesn't fix.
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2answers
96 views

How much clearance through air is required for 10 kV DC?

Suppose I have two uninsulated connectors with 10 kV DC between them. How much clearance through air should I have between those connectors? What table is this found in?
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2answers
46 views

Is there a virtual ground in this op-amp?

Consider an ideal differential operational amplifier whose circuit looks like this, Now in this circuit diagram it is given that, the negative terminal is at 0v. But if I give a sine wave as input ...
2
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1answer
149 views

which is better? 5V or 3.3V as the supply voltage

I am about to design a new microcontroller based project. I checked all components (few) and all can operate at 3.3V or 5V. the microcontroller itself can also operate at 3.3V or 5V (pic micro at only ...
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1answer
63 views

checking for 'dirty' power on a power supply using only a multimeter?

this is a follow up from http://superuser.com/a/958165/43268 It was suggested that i check a 19VDC power supply for "dirty" voltage. If i had a oscilloscope i could probably follow the excellently ...
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2answers
328 views

Determining voltage of fuse

My car battery is dead, and the fuse in my car battery charger is missing....(don't ask me why) I have a 20A fuse lying around and a 7.5A fuse that I took out of the car. The car battery charger ...
0
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1answer
83 views

Questions about LEDs in a circuit [duplicate]

I read statements like ‘An LED has a fixed voltage drop regardless of the current running through it’, but looking at the following examples (using arbitrary numbers), can someone confirm that the ...
0
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2answers
65 views

Arduino digital input - Read voltage slightly higher then 5V - a power efficient solution [duplicate]

I need my Arduino to detect the state changes in a device - (ON or OFF). In order do do this, I have to check the voltage between two points on the PCB of the device. When the device is OFF, the ...
2
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2answers
153 views

Parallel resistor and capacitor in non-inverting voltage follower

For an inverting voltage follower, C1 would be part of an LP filter. But in the depicted non-inverting voltage follower circuit, what is the purpose of C1 (if any)? simulate this circuit ...
0
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1answer
28 views

How to interpret step-up output current with respect to input/output voltage

I have a Pololu 12V step-up converter (U3V12F12) that I'm powering with a 3.7V 6600mAh lipo battery. The idea was to use it to power a dev board that requires a 12V input. The dev board draws about ...
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1answer
98 views

Can water in conduit cause an increase in voltage?

I'm a electrical & solar contractor. We installed a 38 kW system consisting of 3 inverters and (120) 320 watt panels, 40 per inverter. When we energize each inverter the voltage increases all ...
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22 views

Relationship between PNP Collector doping concentration and Voltage gain

For a PNP amplifier with \$ \large V_{in} \$ at base, and \$ \large V_{out} \$ at emitter, given that the voltage gain \$ \large A_v = \frac{-V_A}{V_T} \$, why does the voltage gain drops when the ...
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0answers
35 views

How to (cheaply) generate a low voltage DC analog signal (+/- 14 to 70 mV). 1 mA/cm2

I am looking to generate a low voltage DC analog signal (+/- 14 to 70 mV). I was also looking to incorporate frequency modulation (voltage controlled oscillator?). Would I be able to achieve this ...
0
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1answer
69 views

reduce from 12 to 7.5 volts and can carry 4 ampere

i have 2 servos operating at 7.5 which each of them consume 4 ampere at stall and i have battery 12 volts.i want to make a circuit, buy a circuit or even know if it i possible to make or buy ...
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2answers
39 views

Calculate power supply for step down modules

i'd like to build a system in which there will be step down modules that get their power from an ac-dc converter. there are 5 modules connected to the ac-dc converter (each of them steps down to ...
0
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2answers
59 views

From a 3.3v Pin do we separate Positive and Negative flow? If so, how?

If we do not separate Positive and Negative flow, what is the flow from a 3.3V connection? A Little more background on why I ask this question and my confusion follows I have been reading simple ...
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4answers
223 views

Placing just an LED in a circuit?

Kirchhoff's law states that “in any closed loop network, the total voltage around the loop is equal to the sum of all the voltage drops within the same loop” What would happen if you placed a LED ...
0
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2answers
60 views

Converting a variable voltage to s stepped voltage [closed]

I want to design a circuit that takes a variable voltage (0 to 5v) and outputs a stepped voltage — 0, 1, 2, 3 and 4 volts. So that the output voltage snaps to the closest whole number. It doesn't have ...
0
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1answer
51 views

Designing transistor logic gates

How would one make use of transistor logic gates ? Take for example this transistor AND gate for example . In all logic circuits, the output of one gate becomes the input of another . Here the output ...
0
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1answer
100 views

How does earth ground complete the circuit?

I just started reading a book on electronics and currently reading some concepts of earth ground. I came across a section that mentions practices about grounding as follows: The ground terminal of ...
0
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1answer
42 views

How to safely connect the Arduino 5V Pin with a 5V wall wart and USB TTL converter for data transfer?

I'm currently developing a project that involves components with about 2A current draw. These are controlled by an AVR Atmega168 processor with Arduino bootloader over a CH340G USB TTL converter. The ...
0
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2answers
41 views

How do I provide constant voltage to a load?

Say, I have 5V supply and I use voltage divider to have 2.5V and 2.5V across each of them. Suppose, I want to power a microcontroller (input impedance of 200Ω) which requires exactly 2.5V but once I ...
0
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2answers
80 views

Calculating voltage in a simple circuit

If I had a 12V battery and wanted to use an LED that used 2V and 20mA, then I need a resistor that will drop 10V and provide enough resistance to produce a current of 20mA. Therefore I would use R=V/I ...
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2answers
74 views

Math formulas needed to design an Alternator from scratch [closed]

I'm trying to create electricity using an alternator but I require a few formulas. Are there formulas to calculate: Thickness of wire required. Winding's of copper around magnet required. Size of ...
0
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3answers
95 views

How can I be sure to supply enough current without increasing the voltage? [closed]

I have been trying to supply 5V into parallel-connected components which require a certain amount of current in total. If I wanted to increase the current from my supply, can I increase its current ...
0
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3answers
154 views

What are coupling and decoupling capacitors?

I have come through many places stating capacitors as coupling and decoupling capacitors, but I can't understand what is meant by coupling and de-coupling capacitors? Can anyone explain me what they ...
2
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1answer
130 views

Why inductors lose inductance when connected in parallel?

Generally I can't arrive due to why inductance lose inductance when connected in parallel. If two capacitors are connected in series, the distance between the plates of a capacitor increase and thus ...