# 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).

4,676 questions
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### Controlling output voltage using Arduino

I want to control the temperature of a heat pad, which heats up using a power and ground pin, and is controlled by a pressure sensor. The micro controller I am using runs onl 3.3V but the desired ...
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### Voltage drop on power bench supply for channel being off

If I measure voltage drop between terminals of my bench power supply (spec) I get -15 mV when channel output is turned off. Why it is not reading 0? I believe it's due to internal impedance of the ...
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### connecting pam8403 and bluethooth module in series

I am new to this so I apologize in advance for any rookie mistakes. I decided to make a portable Bluetooth speaker. I have a pam8403 and a Bluetooth module: Both of them require 5 V input. Can I ...
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### Peak Current vs RMS Current when calculating Reactance

I am having a hard time getting a grip on AC circuit analysis. I have been taking my peak voltage/current and converting it to RMS current and RMS voltage so I can use ohms law and things like that to ...
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### Convert\Modify Air fryer from 120v to 220\240

Dash Compact Air Fryer i wanted to ask if its possible and\or practicle to convert an 120v air fryer(1000w) to work on 220-240 outlet ? it has a heat spiral and a fan (if it helps) if more info is ...
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### L298N H-Bridge : Powering 4 motors using (6) aa batteries vs (4) aa [closed]

I am currently wiring up my raspberry pi, H-Bridge and (4) 3-6v ratting motors. My question is, how will performance change based on me using 6 or 4 batteries to power motors? I noticed some tutorials ...
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### There exists 110v/60Hz motors as well 220/50Hz ac motors rating, what determines the voltage of an electric motor?

I have seen the Toms question and answers for what determines the voltage of an electric motor? None of the answers not fulfilling. I was not able to comment to get clarify my doubt, so I’m posting ...
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### Why is this voltage follower not working in Proteus?

I have a 4th order bandpass filter which needs to be biased using 1/2 Vcc. I am trying to achieve this using a voltage follower. The bandpass filter was constructed using Multiple feedback topology as ...
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### PNP darlington pair calculations

I have a 20ohms discharge resistor connected to my PNP darlington pair. I have simulated the circuit in my mobile (every circuit app).please find the attachment for circuit. But here I'm unable to ...
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### Is my radio pulling more current than it should? [closed]

I have an FT-747GX radio that I am using as a RF generator for a plasma cleaning machine. In the operating manual on page 3 it states: I have a power supply connected to this radio which outputs ...
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### How to find the output voltage of a system with a computing amplifier?

I got a question regarding the following system. The only given value is the input voltage $$U_e = 8V.$$ Now the task is to find the output voltage $$U_a.$$ My question now is how do I find this ...
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### Heathkit IP-27 bench PSU min. stays at 0.18V and there is a +0.1V for all the readings?

I've recently acquired a Heathkit IP-27 bench power supply. The supply itself works quite fine except that the minimum voltage it can be turned down to with the coarse adjustment is only 0.18V, doesn'...
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### Magnetic ballast with g23 bulb with capacitor

I am trying to make a UV-b photo-therapy light and want to make sure I'm understanding the circuitry correctly-so i don't hastily burn a \$50 bulb. Im using a Phillips PL-S 9W/01/2P (link here). It's ...
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### How to go about finding the transfer function of a non-linear circuit?

Note: The concept of Transfer Function is only defined for linear time invariant systems. Nonlinear system models rather stick to time domain descriptions as nonlinear differential equations rather ...
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### Making a parallel connection = increasing the total current?

Considering the scheme below simulate this circuit – Schematic created using CircuitLab Am, I understand correct, in real life, if I will step-by-step add the parallel resistors, the total ...
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### Voltage controlled voltage regulator?

I have a voltage that's used to dim a 12V bulb and I'd like to use it to dim an LED instead. My plan so far is to use a triangle generator and a comparator to make a PWM signal with varying duty cycle....
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### How to find the transfer function of this first order active filter?

Going through Design with Operational Amplifiers and Analog Integrated Cricuits, in Chapter 3, problem 3.4 I am asked: The circuit of Fig. P3.4 is a noninverting differentiator. (a) Derive ...
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### Neon Bulb Hold Voltage and Current

I'm trying to modify a neon bulb spice model to simulate a plasma chamber. I've calculated the strike voltage (Vstrike) using Paschens law but I haven't been able to find out what the hold voltage/...
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### Keeping voltage above 3.7 Volt with a lipo

I am driving an audio amplifier with a 3.7V lipo. With a latching circuit in front. [![enter image description here][1]][1] The problem is, that when I turn up the volume, the voltage drops under ...
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### Two-port circuit with input/output duality

Suppose I have a circuit with two ports. One port is considered the input, and the second port is considered the output. Assume it's described via $$V_{out} = \frac{V_{in}}{2}$$ Now assume there's ...
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### Connecting bandpass filter to comparator generating excess noise

I have a band pass filter with a center frequency of 100kHz, a bandwidth of 10kHz, and a gain close to 1. Input signal is 100mV-150mV peak to peak with frequencies varying from 80kHz to 120kHz. I am ...
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### analog signal generator output in Volts vs dBm

I am connecting a mixer to a microwave source and need to be careful of how much power I am giving to the LO and RF of the mixer. If I just stay in the unit of dBm, it would be ok but I became ...
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### Nodal question with current-controlled voltage source connected to independent voltage source

so i've got a question here the question is to calculate v1 & iΦ, of course for nodal analysis (v1/24) + ((v1-(60+6iΦ))/3) + ((v1-va)/2) = 0, but (with va as the node left of 2 ohm resistor) how ...
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### Non-Inverting Single Supply comparator hysteresis is too wide

I am trying to convert an input sine wave to a square wave. The sine wave is centered at 2.5V and has an amplitude of 200mV, with a frequency of 100kHz. I am looking for a hysteresis of 100mV ...
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### Switch module test circuit design

I am doing a project to make a test box that would to test the switch module in the photo below. Please see circuit diagram below for inside of the switch. Please note this switch is not an ordinary ...
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### Find Voltage of inductor in LC series circuit with resistor in parallel

I have a LC resonance circuit with a resistor between the capacitor and inductor: simulate this circuit – Schematic created using CircuitLab I want to find the Voltage at L1, more specifically ...
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### What is the turn-on and turn-off condition of the npn-transistor?

Following is the circuit I have been analyzing. My intention is to calculate the turn on and off condition of the transistor Q1. R1 and R2 (10 kΩ each) are internal to the transistor. simulate this ...
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### Mini 360 buck converter: 5v to 3.6v possible?

I am new to electronics and for my first project, I am using an esp8266 12 e WiFi chip to put together an air sensor web server. My breadboard prototype works but I want to add some other sensors ...
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### Designing a circuit that opens when less than 12 volts are applied and closes when more than 12 are applied

I'm looking to build a circuit where current only flows when there is a potential difference across the entire circuit of more than 12 volts (+- 0.1 V). I also need there to be only a small amount of ...
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### Linear Voltage Reduction Device

I need to lower a 12v, 100mA signal voltage to a 5v signal voltage of any current rating. Here's the catch: I need that 7V drop to be constant with any input voltage. For example, since it is a signal ...
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### Tower Sawyer Circuit - High impendance DUT

I am trying to assemble a Tower-Sawyer circuit for measuring Ferroelectric loops. On a picture below you can see the most simple design of Tower-Sawyer circuit, with a parasitic capacitance in ...
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### Why is current controlled feedback faster than voltage controlled feedback in PWM controllers?

Looking at modern ICs, we prefer current control feedback over voltage control feedback, due to the speed of the feedback. Current control will react faster than voltage control. Here are 2 images, ...
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### What is harmful for electronic circuits? Voltage or electrical current?

Its said that if you get more electric current, the electronic device in a circuit will just take what it needs and its not dangerous, so if we raise the voltage and therefore the electric current ...
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### Instrumentation Amplifier - is it possible to have an output signal inverted, with respect to the supply voltage?

I'm doing some circuit design in order to translate a load cell input into the pedal input of a Logitech G27. What I want to achieve involves having a balanced state output as close to 5V from the ...
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### Voltage in a Y-Δ transform

I'm looking for a way to solve the following circuit Without the voltage sources on the circuit, I would be using a simple Y-Δ transform. But I'm not sure how I should proceed with them on. Which ...
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### why would Ix would be 0?

Current coming out of the 5V source would never be 0 so what would make the current coming out of the 3v dependent source 0?
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### How can I use a US 120 volt Ryobi charger From a 220 volt main? [closed]

I bought a ryobi kit in the us and I want to use it in in Europe. I doubt that I can plug it directly into the socket, what kind of converter/adapter do I need? Is there a way to adapt the charger ...
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### Why do we need a chain of resistors to increase the voltage? [closed]

I did a workshop on SMT today and we made this board attached. However, what I don’t understand completely is the logic: why do we need 3 resistors to increase the voltage (on the boost part)? What do ...
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### Replacement battery voltage mismatch tolerance?

I want to try replacing a proprietary battery in an electronic of mine as a first electronics DIY project. Thing is, the stock battery is 3.6V, and the phone battery I have on hand that I would like ...
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### Cause of triode mode in MOSFET

My reference text introduces the MOFSET as follows: The text says the induced channel has uniform width as long as $v_{DS}$ is small, because in that case $v_{GD} = v_{GS} - v_{DS} \approx v_{GS}$...
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### Run actuator at higher voltage and with lower dutycycles

I have an actuator which is rated at 12 VDC input voltage (0-15) with a maximum allowed duty cycle of 20%. The already existing voltage levels in my system are 5V and 22V, and since I am weight ...
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### Is diode with forward voltage ~0.15v faulty?

I tested a diode model SB360 PFS which it showed about 0.15 forward voltage. The reverse voltage is zero. Looking the diode specification I read that Vf is 0.49v to 0.68v. So my question is if this ...
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### What does “Run Power and Ground wires back to the Arduino” mean?

An Adafruit article showing people how to wire up an RGB LED to an Arduino UNO has the warning shown below on its page. For longer strips requiring more than 1 Amp, wire the power directly to the ...
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### Off load voltage in npn transistor as a switch

There is transistor tutorial on sparkfun.com (https://learn.sparkfun.com/tutorials/transistors/all). I am wondering why there is 1.3 V drop depicted across the LED1 on the picture, since when the base ...
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### If amps and volts can vary independently, how does Ohm's law actually work?

This is a very basic question as I'm just starting to get into things, but I've hit a roadblock with comprehending the definition of voltage as it relates to the relationship defined in Ohm's law. It ...
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### What is line to line voltage supposed to meter at?

I'm pretty new to this but I know that in three phase power, when I'm metering line to line its usually at 208V, but I've been told that line to line meters at 240V. I don't know what would cause for ...
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### JFET Voltage Divider design question

I've been trying to get this question done for a couple of days now and no matter how much I try I've been unable to get it done. Your help in this question is greatly appreciated.
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### 9V Battery Current Range

What is the range of currents that I can safely draw out of a 9V battery without damaging it? I am planning to design an experiment and I don't want to draw too much of current out of a battery and ...