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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Three devices connected to one battery [closed]

What battery voltage do I need when I connect three devices (the tracking device, a siren alarm, and a bulb in a flashlight)?
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How much more efficient is 240 V than 120 V?

I've got a PHEV that currently uses a level 1 (120 V) charger, which works fine and can do a full charge overnight. It's fairly trivial to upgrade to a 240 V circuit, but I'd have to buy a level 2 ...
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Circuit Analysis: R3(Missing), Voltage(Missing) [closed]

This is a very simple circuit but I cannot solve it as I'm very slow in circuit analysis. Hence, I'd like to ask if someone can show me how to solve this one.
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1 answer
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I want to make a voltage limiting circuit

I want to make a simple circuit that gives a constant output voltage regardless of tiny fluctuations in the input. Is it possible to make it so that when the input is off, the output is off, but when ...
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2 answers
53 views

How are the transistors in motherboard controlled and timed?

I just watched Bullzoid/Actually Hardcore Overclocking's video on how VRMs actually work, and I have a couple questions. In the video, the Bullzoid mentions how the transistors are switched on and off....
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Across which terminals is EMF induced in this circuit?

If I were to place a circuit such as this in a changing magnetic field, across which terminals would an EMF be induced? If the field were into the plane My intuition suggests across all wires lying ...
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1 answer
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Query regarding 9 V battery connection to 7408 IC

I have got some LEDs, a breaboard, a 74HC08 IC, a 9 V battery, resistors of 10 and 100 ohms. I want to check the IC by connecting it to a breadboard but the IC input voltage is 5 V and current 8 mA. ...
1 vote
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Multiple feeds from a single AC source

Rather than have a line of plugs in a 3-gang extension on top of my kitchen cabinets, I thought that if I split the feed, then fuse and switch each power supply for each LED strip, it would be an ...
1 vote
2 answers
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Slight confusion on voltage calculation

I have this circuit, and I'm trying to understand how the solution arrived on an equation involving the open current voltage V_th, in particular, the bottom equation: Vth = V_12ohm - V_3ohm. Where ...
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3 answers
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What adapter do I need to replace 4 AA batteries?

I have Yale Linus lock installed at my home. It has 4 AA alkiline batteries inside, and it grinds through them like hot knife grinds through butter. Therefore I want to convert it to an AC powered ...
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Stepping down low voltage AC

This seems like basic Ohm's Law electricity stuff. But before I blow something out, I want to get a second opinion. I have a model train transformer the has a 20 volt AC accessory output. I ...
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Magnetic levitation without any microcontroller

The above image is taken from here. It uses an electromagnet with two sets of windings which have DC current travelling opposite each other to generate eddy currents in the aluminium plate which helps ...
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55 views

Multiplexer voltage reference

There is a potentiometer on a circuit board that I want to simulate with a DAC. I want to be able to either use the original voltage from the potentiometer or simulate the voltage from the DAC, hence ...
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Will these 2 electromagnet produce a 40kg (400N) attractive force?

Dear all, theoretically according to the electromagnet datasheet, it can attract with 20kg force, does that mean if I have 2 of the same electromagnet and if I switch it to different polarity from ...
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Reflected output voltage (VOR) in a transformer

What, exactly, does VOR mean, and how does it affect the number of turns, output voltage and controlling circuit in a flyback transformer?
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Push button is reducing voltage

I'm making a little flashlight that'll turn on and off with a push button, but the problem is that my push button changes 3.2 V into 2.8 V. I don't know if it's a normal issue or how to fix it. Any ...
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6 answers
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Grayscale using LED

If I took a regular LED that is either on or off, the brightness of which can be controlled by the amount of voltage it's getting, then at half power I could in theory get a 3rd "shade" ...
3 votes
2 answers
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RLC resonator to produce beautiful sine wave

simulate this circuit – Schematic created using CircuitLab I have read about the RLC tank which can help to resonate a pulse wave of a certain frequency so that it will produce a beautiful sine ...
4 votes
1 answer
666 views

LTspice capacitor bug?

I know that capacitor slows the rise of voltage, but why is this not happening in the LTspice simulation? I got the input voltage at the output instantly.
1 vote
3 answers
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Configuring regulator shut-off

I'm building a regulator based on the TPS63020 buck/boost converter, and I'd like to program a low-voltage shut-off. If I'm understanding it correctly, when VINA sees a falling voltage and it crosses ...
1 vote
1 answer
107 views

Multimeter doesn't measure 0V

I am working with an Arduino Nano multimeter. The multimeter has an internal resistance of approximately 14 MΩ. When the probes aren't connected to anything I don't get 0 V. When they are connected to ...
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Measuring EMF and terminal voltage with multiple batteries

Suppose we have two 12V batteries as our source voltage. How can the EMF and terminal voltage be measured when using one 12V battery versus both batteries? Since terminal voltage deals with a closed ...
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3 answers
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How do we use step-up transformers to get a very high voltage compared to the initial voltage?

In some medical equipment like CT we find that the voltage entering the equipment is around 380 V, but then it's increased to be around 70 kV to 140 kV. To increase voltage we use more turns on the ...
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Dropping voltage output from my 4S battery pack to inverter

I'm making a battery pack for my inverter. It's a 4s20p, 2 Ah cell; output is 16.5 V when fully charged The inverter itself can only take 9.5-15.5 V input, with 1000 W peak power and 500 W continuous ...
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4 answers
381 views

Why does capacitance affect the charging time of a capacitor?

I'm trying to understand the relationship between the capacitance with the voltage output of this circuit. If the capacitance is greater, why does it take more time to charge the plates of the ...
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How to use Kirchoff's voltage laws in an AC circuit?

I apologize for not having any examples, but I'm asking this just in case I get a question like this in my exams. In a standard DC circuit, Kirchoff's law states that: $$\sum\limits_{i = 1}^n {V_i} =...
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2 answers
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Op-amp stable voltage gain out of different input value

Can anyone tell me how to make a circuit with unstable input voltage signal value to a stable output value For example: A sinewave in the input between 1 Vrms to 5 Vrms The output must be a stable 10 ...
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1 answer
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Why is the instantaneous magnitude of current and voltage in a phasor diagram given by the vertical components of the phasor vectors?

In general, if a phasor is rotating, the instantaneous voltage is given by \$i_m\sin(\omega t)\$ where \$i_m\$ is the amplitude of the current. Similarly, voltage is given by \$v_m\sin(\omega t)\$ ...
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Explanation of PCB specification

I'm using this IC - USB5816 SS In this application note, Link, page 7, it is given as, "Consider laminates with low Df ratings at 10 GHz. These lower loss materials include FR408HR, FR408HRIS, ...
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2 answers
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How does lightning increase the voltage within a substation (how does current increase voltage)?

I'm new within the power industry and was introduced to a scenario I had a question about. So, while discussing the need for surge arresters came up, we began talking about lightning. I know that ...
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1 answer
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Simple 3.3 V to 12 V voltage level translator on data bus

I would like to build a nixie tube clock with a unique idea. The idea is that the clock queries the accurate time (it respects the DST too) from my home server. So the clock does not require any ...
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2 answers
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Can 12V/9V DC source be used for Christmas Disco Light instead of 220V AC?

the Christmas disco lights up on 220V AC supply. Now, can I used 12V/9V DC at the points A and B (picture attached)? And, will the lights work as before in AC source supply? If not, please enlighten ...
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4 answers
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Why does the L298N schematic supply Vcc to diodes?

I have been studying the L298N motor driver module to re-implement it as an exercise to learn PCB design. Something I am confused by in the schematic of the module is why Vcc is supplied to the diodes ...
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How to calculate voltages in op-amp circuits?

I don't know how to solve the following problems; I don't even know what the best way to start solving them is. Can someone help me with the calculation steps so I can then try to solve them on my own?...
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Voltage divider for 14.8 V Li-po to power 7.4 V servos

I'm wondering if there's a more straightforward solution than using a step-down converter for my robot. The robot is mobile, so it needs to run on rechargeable batteries (Li-po). I'm using a Jetson ...
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Why can't I power everything with a 9 V DC battery?

I am a student and have a very basic knowledge of volts, ampere, watts, charges, etc. My question is fairly simple: Why can't we use 9 V DC batteries to run everything in the world? Because it's DC, ...
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1 answer
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How to increase the voltage of a power source? [closed]

We have a USB 5V 3A. How can I increase this voltage to 12V with losing current level? I need 12V 1A. I need a circuit drawing which I can assemble for this. How to preserve power (15 W), and not ...
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Voltage regulation on a relay module

I have an Arduino project which involves turning on a couple of devices which require an input voltage in excess of 5 V. I have successfully prototyped it using three Grove-Relay modules. I now want ...
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Connection of two ICs in the same PCB

I'm having 2 ICs. LAN9500A and 88E1510. Both of these are in the same PCB. I'm connecting the MDI lines between the LAN9500A and 88E1510. In that case, can I use capacitive coupling mentioned in this ...
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Can I use an American power strip in a European outlet? [closed]

All my devices can take 110-240 V. I need to connect six of them and I only have a European outlet (any type) and an American power strip (with plug adapter). Considering voltage will arc at 1 kV/mm, ...
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Charging my 18 V mowing robot

I have a mowing robot, Bosch Indego 500 S. It says it has an 18 V lithium battery. I would like to charge it with a battery. I can only find 12 V or 24 V batteries in the stores. Is the 12 V still OK? ...
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Cascading resistors in series

Suppose, let's assume an IC pin requires a 10kohm 1% tolerant resistor connected to ground for its proper operation. In that case, can someone tell me whether I can split the required resistors into ...
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-1 votes
2 answers
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How do you solve for current or voltage in series circuit when you only have resistance total and P1? [closed]

Total resistance 900 ohm P1 is 48mW Needing I or V to solve the rest of the equation or power total
1 vote
3 answers
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How to calculate the AC current consumption of an external power supply if I only know its DC volts and amps output

I'm working in an AV project and need to calculate the total AC current consumption of an AV equipment rack for the electrician to calculate breakers and the electrical installation, but some of the ...
3 votes
1 answer
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Awesome magnetic levitation using Arduino

I followed a Youtube video here and it has instructions at here. The concept is easy which is try to levitate a magnet and balance it using Hall-sensor by changing the PWM of the electromagnet to ...
-1 votes
0 answers
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Is it OK to use a lower voltage rated momentary switch if I have a resistor inline?

I am planning to build a 48V LiFePO4 off grid solar system. I am trying to add a pre-charge resistor to the design to prevent a large inrush current to the devices. I want to add a momentary button ...
1 vote
1 answer
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Connecting 12 V RS485 appliance (soil sensor) to USB 5 V RS485 adaptor

I have a 12 V RS485 appliance that measures some soil resistance etc. It is a 7-in-one soil sensor, the 12 V version of the 5 V version shown in the link. I could not find a 12 V USB to RS485 adaptor ...
5 votes
2 answers
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Compute voltages and equivalent resistance in the presence of a bridge

Problem. Given the circuit in the figure, I wish to compute the equivalent resistance between node A and D, voltage \$V_{\mathrm{BC}}\$, both under closed and open bridge K. \$R_1=50\,\Omega\$, \$R_2=...
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1 answer
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54 V input on one, or two 40 V linear regulators? (LM317)

Before I explain the situation I am in, please bear in mind that I am completely new to electronics, and I want to spend as little money as possible on my current project because of outrageous pricing....
2 votes
1 answer
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Why is the scope showing half the value of the function generator?

This is a follow up on this question: Oscilloscope voltage not matching function generator When the function generator is set to 50 Ω (Rint), it automatically assumes that the external load Rout (...
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