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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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Passing greater of 2 voltages using 5V signal

I need to output the larger of two voltages (Va, Vb) (both of which could be in a range 0-30V), but drive the circuit using a 5V supply. A simple solution (using op-amps, FETs) is needed. I have ...
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181 views

Protect first LED (W2812b) in line from voltage spikes?

I am currently working on a Arduino / Raspberry Pi project, where I am trying to drive a line of 64 PL9823 LEDs which are said to be equivalent to the popular WS2812 LEDs. Datasheet: http://www....
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156 views

Output voltage of USB FAN

In my recent project, I'm working on 5V DC USB fan's speed controlling. My fan motor looks like below: Here fan controlling is done by PWM which is coming from Arduino NANO controller. For ...
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9answers
8k views

What exactly is voltage?

Bit of a strange question, but what is it? My physics teacher said it was kind of like a "push" that pushes electrons around the circuit. Can I have a more complex explanation? Any help is much ...
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897 views

Why does voltage split when an additional resistor is added?

When you have one resistor in a series circuit, the amount of voltage taken up by that resistor is 100%. Adding another resistor (same Ohms) makes that voltage drop 50%. Why, since only current should ...
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55 views

Is my radio pulling more current than it should?

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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3answers
994 views

How to measure Inductor maximum current?

I have an inductor and seller claims that inductor supports a maximum of 5A current and he asked me to test it myself. Can someone help how to test that how much this inductor can support/ draw ...
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24 views

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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2answers
155 views

4-20mA loop voltage to high

I have a 0-16 bar pressure probe connected to a module called Adca UD-720. The probe works on a 4-20 mA loop and the readings are ok. This module also has a 4-20 mA output and I need to connect this ...
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71 views

How much does Voltage matter [on hold]

I've created a battery pack of 10 double-A's; eight in series and 2 parallel. My volt meter reads 10.78 volts but the unit I'm powering only requires 9 volts. What are the chances that extra 1.78 ...
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9V battery and resistor are connected in series - the voltage across the resistor is < 9V. Why?

I am taking my first steps into learning about electronics as a hobbyist and I am struggling to understand something about resistance. I have read about Ohm's law and it seems fairly straightforward ...
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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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111 views

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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1answer
22 views

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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1answer
160 views

Instantaneous phase voltages of 3 phase WYE load

If phase 1 instantaneous voltage is 100 v and decreasing what are the other phase instantaneous voltages if the max voltage of phase 1 is 170 V? Frequency equals 60 HZ. (60 Cps). I do not understand ...
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39 views

using 12/20kv cable on 3.3kv system voltage

could we use 12/20kv (24kv) cable to replace 3.6/6kv (7.2kv) cable in 3.3kv system voltage? what is the standard reference?
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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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0answers
69 views

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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3answers
25 views

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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1answer
165 views

UL Clamping Voltage Ratings on Surge Protectors

I have been looking for some new surge protectors for my devices, and I am having trouble understanding the meaning of the voltage clamping ratings on many surge protectors. It seems that all of the ...
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1answer
45 views

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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1answer
228 views

Calculate battery state of charge percentage

What is the correct formula to calculate battery state of charge percentage based on the battery type (12v, 24v, 48v and so on) and the current battery voltage. For example if I have a 12v battery ...
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2answers
59 views

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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0answers
36 views

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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2answers
10k views

When is the AA battery voltage drop?

I have a device which is running on two AA Duracell batteries. The batteries (brand new) together is producing 3.2 volts (1.62 volts individually), which is estimated to run for at least 2 years. The ...
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1answer
49 views

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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2answers
1k views

Controlling fan speed with a rheostat

I just got a rheostat from radio shack to connect to my homemade stir plate. The rheostat looks like: (from here) My question is, how do I set it up? I want to use it to vary the fan speed. I am ...
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0answers
14 views

Voltage for SE501TS [closed]

What is the voltage for driving the LED strips in a 50 inch Seiki TV, SE501TS? I'm getting exactly 75 volts, which seems reasonable.
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0answers
46 views

Power lines material conductivity [closed]

Why dont they place a coating around the poles holding up the power lines so that when somebody touches it, they wont get electrocuted?
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1answer
82 views

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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1answer
38 views

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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2answers
40 views

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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1answer
169 views

Effect on LED driven at a higher Voltage than maximum forward Voltage

My current PCB configurations are (10 series 4 parallel)x3 in parallel making 10 series and 12 parallel I am using Meanwell ELG-75-42 driver giving a voltage of 42V at 1800mA, and a power of 75W. It ...
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1answer
177 views

Order capacitors by leakage rate in Cockcroft-Walton voltage multiplier

Looking at a system like the Cockcroft-Walton multiplier posted here: https://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/voltage-multipliers/ To use 400V 100uF electrolytic capacitors ...
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0answers
44 views

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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50 views

18650 battery charging [closed]

I have 2 18 650 Samsung 25r batteries that I charge as a couple always yesterday one of the batteries read 4.21 volts and kept charging on a smart charger is that bad what was going on is it the ...
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1answer
416 views

Circuit analysis - laplace transform

So i have a circuit where R1 = 5 W, R2 = 2 Ω, L = 1 H, C = 1/6 F ja E = 2 V. And i need to figure out what is iL when t=0.5s with laplace transform. Switch opens when t=0 When t<0 i got ...
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2answers
60 views

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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2answers
508 views

Reduce 6 volts to 5 volts?

I want to install a Siriusxm radio receiver in an antique car with a 6 volt system. The Sirius receiver 12 volt power adaptor states that the output is 5 volts. If I wire the receiver directly into ...
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3answers
430 views

Analog (POTS) telephone off-hook detection

With a single POTS telephone line and two or more handsets, when a call comes in, each handset can join in with the call. This can sometimes be an issue when one user doesn't know the line is in use, ...
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1answer
193 views

What is the benefit of driving the HV5622 chip to the recommended operating voltage?

I am a beginner in electronics. I want to use HV5622 serial-to-parallel converter to drive nixie tubes. However, there are two types of datasheets: Recommended condition and absolute maximum ratings. ...
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2answers
85 views

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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2answers
61 views

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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0answers
32 views

What would be a good constant source of power for a motor? [on hold]

A couple of friends and i want to build an orrery. We are having trouble in figuring out what would be a good power source for our motor. We are planning to use one motor to run the central gear ...
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6answers
75k views

“Ground” vs. “Earth” vs. common vs. negative terminal

This may just be me not having a degree in electrical engineering or electronics, but the whole notion of "ground" and "earth", when used in electrical circuit diagrams (especially integrated circuits)...
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1answer
35 views

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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3answers
2k views

Minimum clearance between two traces that have a potential difference of 1000VDC

I am designing a PCB and there will be high voltages. What is the recommended clearance that I should have between two traces that have a voltage difference of 1000VDC and 2000VDC? Additionally, is ...
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0answers
63 views

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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1answer
82 views

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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4answers
319 views

OFF grid solar batteries - dropping voltage

I have 4 x 12V AGM deep cycle batteries configured as 48V 200AH. these are powering my home at night and are managed by SMA sunny island 6OH, in conjunction with SMA sunnyboy 3000TL and 4kw of solar ...