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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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Understanding Voltage Amp in my simple circuit

Hopefully its OK to ask very basic electronics questions here. I had a TTL 5V UART cable, the board I had only accepts 1.8V max. So I found some online schematics that uses resistors and transistor ...
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Will a diode change how my IC works?

If I have an IC, any IC, with a V+ and a V- that has a minimum voltage requirement of 3V to operate. Say I supply that exact 3V, but I want to add a silicon diode to the V- to prevent a reverse ...
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On a 3-terminal bench power supply (+, -, GND), are there positive and negative drivers behind each of the terminals?

In a 3-terminal power supply like this, are there individual regulators behind the positive and negative terminals? For example a LM317 on the positive and a LM337 on the negative? If not, what kind ...
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Are my op amp nodal voltages correct?

I am wondering if my assumptions are correct. For the circuit attached I assumed that Va is equal to Vb and which will be equal to Vc since the difference input voltage must be equal to zero.
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Earth Fault in a TT Network: Current loop, or charges flowing from one grounding to the other?

There are serveral things I (yet) don't understand about the T-T-earthing system. The most important one is that I don't understand which way the the current takes in case one of the conductors (for ...
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Artec QDD2 reverse voltage problem

Good day everyone, I have an Artec QDD2 overdrive circuit and I recently powered it up with reverse voltage by accident and it doesn't give any sound on the stages of distortion, however it is ...
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36 views

Alternating Voltage

Is AC the same as an alternating voltage ?
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Can you convert a small gas engine 220 volt starter to work with 120V?

My snowblower has a broken connecting rod so time for an engine replacement. Good price on a new replacement 11HP gas engine on Ebay but it's set up with a European 220 volt starter. The 120 volt ...
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88 views

Where do I place the on/off switch in a multi voltage circuit?

I've got a simple Arduino setup where I need to supply a 3.3V Arduino with adequate power - and at the same time provide higher voltage to a sensor which needs 5V. The Arduino is powered by bypassing ...
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57 views

Circuit that averages voltage

Suppose we have an oscillating signal V(t) with V(t) >= 0. I'm looking for a circuit that averages this signal over a given time so that I can read out the average value directly using a simple ...
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33 views

Protective-Earthing the chassis with the earthing point being the star-point - How does it keep the Chassis at Earth potential?

I always understood that one of the two purposes of protective earthing is keeping the electric potential difference between the chassis of a devide and the ground (the ground I am standing uppon ...
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Can open-circuit voltage be treated as voltage to find power dissipated? [duplicate]

Can open-circuit voltage be treated as voltage to find power dissipated? I combined all the resistors (including Vlamp) to get one resistor of 40/6 Ohms (Correct me ...
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Can a Current Limiter Power Thermistor be used in line to reduce the brightness of a 120v incandescent bulb?

I have an application were I do not have the room for a dimmer switch but need to reduce the lumens of a 120v 25w incandescent bulb just a bit. There used to be a product called the Bulb Saver Button ...
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118 views

What is the best way to get 7V from a benchtop 10V supply?

I have a 50 ohm load I am trying to drive at 7V. I currently have a 10V supply with a 10kohm potentiometer but I am expecting to run into trouble when I connect it as a voltage divider. I looked ...
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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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Voltage drop across buck converter

In my robot, I plan to have a GPIO pin on my Raspberry Pi connected to the insertion detection pin (pin 3) of a barrel jack (schematic here) so that my code can tell when the robot is externally ...
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Voltage law not correct [on hold]

Is the voltage wrong? Across the resistor there cant be any voltage drop because the electric field of a battery that forces the electrons to move is constant for all points inside the conductor.Just ...
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33 views

How can I check the voltage of a fan?

Is there a way I can connect 1 or 2 batteries to a CPU Fan that I dissasembled to check what voltage it is so I can use it at the highest speed?
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73 views

Elimination of interfering voltage

I have a problem deriving a formula I will be using in my bachelor thesis. It's about eliminating interfering voltages during measurement. To understand how the interfering voltage is going to be ...
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3answers
38 views

Why does current not increase when the voltage increases in this case?

When talking about BJT transistors, a very common graph is the one shown below, that plots (VCE,IC) as an ascending function. As far as I know, the BJT manages VCE so that IC is beta times IB, being ...
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119 views

Voltage divider resistance/wattage sizing

I am working on a small project currently -- I recondition hybrid car battery packs with a grid charging system, and I am working on a voltage sensing circuit that's monitored and available via a ...
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52 views

Dramatically increasing voltage in a circuit

Suppose I have a small AC generator, which produces an unstable current at 1 volt. How can I transform this into 10000 volts, decreasing the amperage accordingly? It does not matter if the output is ...
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39 views

voltage transient protection for MV Motors

What types of transient voltage protection is applied on medium voltage motors and are these types of protection that are applied depended on the type of motor it is e.g Synchronous vs Induction motor?...
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55 views

Measure voltage of the panel light bulb inside a vintage radio

I'm new to Electronics. I have recently received a vintage radio Pioneer TR-305. I am trying to replace the panel light bulb inside this radio. I opened the radio panel and found the bulb soldered ...
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Can I use this relay?

I got this relay. In the product description they say: "belastet bis zu 10 Amp/250 VAC, 5 Amp 30 VDC." which means: "charged up to 10 amp / 250 VAC, 30 VDC 5 Amp". On the relay it is printed: 10A/...
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How does one determine the type (AC v. DC) and operating voltage of small motors?

I've become fascinated by Rolling Ball Sculpture (RBS) and plan to start building my first one soon. Typically a RBS uses a low-voltage, low-RPM motor to carry the marbles to the top of the structure ...
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HV Capacitor power [closed]

Hi does anyone know what kind of high voltage power DC supply do I need using UK 50Hz to charge a high voltage capacitor 50/25kV.
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206 views

How can I change step-down my variable input voltage?

Ok so here's the deal: I have a variable DC Voltage source from 0-10V. I need to step that down to a variable source of 0-3V. This 0-3V DC will be fed to an Analog to Digital converter in a ...
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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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64 views

Clipping an AC line voltage

I've got a linear step-up transformer (120V AC input) which has an output that under load nominally supplies 230V AC @ 100mA. But with no load it floats to as high as 280 V. I need to switch the load ...
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Is there any 433mhz rf transmiter/module/transceiver can work at 1v voltage or lower? [closed]

I am finding this kind of transmitter but it seems there is no such kind of components. Does anybody know? Thanks Because I want to use a msp430l092 which work can at 0.9v at least. Combining it ...
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218 views

Potential difference and current flow

I've been taught that electrons move from cathode to the anode (negative and positive). But what happens when I apply positive voltages at +10V at one end of the circuit and +6V at the other? How ...
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2answers
106 views

Building a midi project with Arduino + scrap components (optocoupler and diode)

Original title: 300V output Optocoupler in a 5V circuit I'm (new to this) trying to build a midi controller (in and out) with arduino and scrap. I guess I had several questions in one so I changed ...
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34 views

Clamper circuit, how to apply kirchhoff when the diode is turned around?

in this clamper circuit it's easy for me to determine the output waveform: This is how I do it: In the positive half cycle, the diode is forward biased with a drop of 0.7 V, so the positive half ...
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3answers
72 views

About dynamic equations and the transfer function for the circuit

/ Attempt Follow my setup $$v_1=u_2$$ $$i_1=C\frac{du_2}{dt},v_2=L\frac{di_2}{dt},i_2=\frac{u_2-v2}{R_2},i=\frac{u1-u_2}{R_1}$$ According to KCL: \$i=i_1+i_2\$ Let \$s=\frac{d}{dt}\$ Get \$R_2(...
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How to convert a 3.3V signal to 5V for a Mosfet gate

Based on the question 4-5-v-on-gate-of-mosfet-while-switch-open I ask this more generic question. Main project: I want to create a 16x8 (or so) multiplexed LED circuit Sub project: Creating a 2x2 LED ...
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1answer
58 views

DC Shunt Motor Load Loss

I have three DC shunt wound motors in series. Each motor has a coupling to a transmission. I am trying to work out (mathematically, as opposed to intuitively), what happens if the coupling was to drop ...
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1answer
27 views

STM32F429ZI reference voltage

I want to use the full output resolution of DACs (12bit) in the range of 0-1 Volt (and not in the range 0-3.3 Volt). I see there is a pin VDD in this board (STM32F429ZI), please help me to understand ...
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Amperage rating of electrical panel [migrated]

Replacing a sewage pump for a building Existing panel is Challenger Electric J94 Company discontinued so unable to find amperage I know the Voltage-Motor Horsepower rating information. What is the ...
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3answers
91 views

Why is the output frequency of the zero crossing detector (square wave generator) double that of the input signal?

I have built a zero crossing detector that acts as a square wave generator according to the circuit diagram shown. It is connected to a potential transformer. The output from the potential ...
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3answers
323 views

The Ohm's law calculations of the parts do not agree with the whole

In the circuit below, the Ohm's law calculations of the parts do not agree with the whole: the voltage drops of the parts do not add up to the total voltage, and the current does not calculate to be ...
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1answer
47 views

Does battery wear depend more on EMF voltage (capacity) or terminal voltage? (charging full slowly vs. charging fast)

Let's say there are two identical Lithium-Ion batteries. (is it any different for Ni-MH batteries?) One gets charged at 0.1C until the EMF voltage (which is capacity-dependent) reaches 4.3V. The ...
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2answers
65 views

boost converter circuit behaving strangely

I built the following circuit: The boost onverter works fine when applying 0.5 time ON PWM signal (Vout = 2.5V) but when I try to increase the voltage using 0.8* time PWM signal the Vout** stays ...
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3answers
844 views

In which way proportional valves are controlled solely by current?

Proportional valves are drived by current because we need a steady force and since resistance changes with temperature if they were driven by voltage this force wouldn't be steady. Ok, this is what I ...
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56 views

Power source project

I’m currently a computer engineering student from lorma colleges and we’re currently doing our design project. Our project is called an advance helmet. A helmet that is capable on creating a ...
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39 views

Powering multiple Laser Diodes

Hi I am working on a project that has 6 laser diodes. each pair has different voltage requirements. They are 7V-10V, 3V-5V, and 3V-5V. any suggestions to how I could power each together with one board?...
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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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2answers
110 views

How do devices that are rated for 120/240 volts work?

I am about to go over seas and when considering powered items I am bringing, some things state they can take both 120 and 240 volts. What do devices usually do to make sure their output is the same ...
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29 views

Electronic Ballast Assistance

Please see attached image of wiring diagram. The isolator, MCB and contactor are installed upside down in a control panel. If I modify these components and install them correctly (although wiring ...
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2answers
290 views

LM22678 Unstable output

I am building a voltage regulator with the LM22678-5. I used TI WE-Bench designer to get the component values needed for the regulator: The regulator outputs 5V when there is no load however it ...