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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200mA constant current @ 6V from 12V battery

I have made a digital speedometer with a Hall-effect sensor, but while the battery is discharging, sensor output also changes. I need a circuit that consumes the entire battery capacity, that is, from ...
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120 views

Does a DEcoupling (intended) capacitor cause phase shift? [on hold]

"Will a coupling capacitor cause a phase shift to an IC chip input pin? The input signal is AC." 22nd July 2014 Yes, I would like to reiterate this weird question: The input is a signal will ...
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1answer
83 views

Minimum number of capacitors

I require a capacitance of 2×10^-6 F in a circuit across a potential difference of 1kV . I have a large number of 1×10^-6 F is available which can each withstand a potential of 400V. Suggest a ...
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2answers
84 views

What is the audio voltage of an android phone?

For a project I am currently working on, I need to use the audio output of an android device. Is there a standard max voltage?
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88 views

Voltage decreases on higher current

I have a circuit composed of Arduino Mini Pro 3.3V and GY-GPS6MV2 (GPS Ublox NEO-6M). I have tried to power it with 3 different sources: 3xAA NiMH in serie connected to RAW pin of Arduino and using ...
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91 views

how to provide a steady voltage, in case of source voltage drop due to heavy consumers in the circuit

I am designing an arduino circuit in which the power source is a battery connected to some heavy current consumers, these consumers are intended to work for short time and infrequently, my question is ...
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3answers
68 views

Battery current reduction [duplicate]

I have made this circuit: Now I am trying to use this circuit in my bike. My bike has a 12V 9amp battery and while charging (bike running), the voltage fluctuates from 12V to 20V. To power this ...
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28 views

Control automotive AC switch via TPS voltage

The A/C compressor is engaged via a single wire that comes from the 'A/C' button on the dash board. I want the A/C button to disengage when the throttle is at 50%. The throttle position sensor (TPS) ...
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6answers
150 views

How can voltage actually exist/change if electricity can't actually speed up or slow down? [duplicate]

PLEASE NOTE: No this question does not already have an answer at the link posted above. This question was closed by individuals who didn't read it, nor the comments underneath it. I am new to ...
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6answers
174 views

Given a known power supply, what are safe ranges for the volts/amps/ohms of connected components? [duplicate]

I'm new to hardware and am coming from a software background. I have an SoC that will be powered by a supply generating 5V and 1A. I'm trying to figure out what are the safe ranges of volts/amps/ohms ...
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53 views

Low current (~100ma) buck voltage converter simple, low cost options (48V to 12V)

I have 48V AC-DC power supply that I use to drive high power LED drivers. I also want to use the same 48V input to power a 12V fan and Arduino Pro Mini. Fan is rated at 0.25A but I could do without ...
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3answers
91 views

With a transformer center tap, why are the two resulting circuits out of phase by 180*?

I'm trying to understand how the power in my home works, and the part I'm having trouble with specifically is why in the step-down service transformer, the resulting out-of-phase 120V "hot" lines are ...
2
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1answer
75 views

From node to node, do units of charge lose energy over a constant period of time?

I have the following circuit set up on a breadboard, and I've measured current and voltage between each node. Current everywhere is .02A, as expected, and my resistor came out to 217R. simulate ...
4
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3answers
137 views

Thermistor control of peltier voltage with Arduino (for DSLR chill box project)

I am mildly familiar with electronics, mostly from playing around with electronics kits as a kid. That was a long time ago, though, maybe as much as 20 years ago. I am currently working on a cold or ...
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1answer
55 views

I want to adapt a VFD

If I feed single phase electricity into a 3 phase input VFD, I know it needs to be derated on the output by about 50%, but how does it cope with the difference in voltage, as rectified 230v rms gives ...
0
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1answer
27 views

Slow fade option with an LM3914 IC

I have been researching the best circuit design for LED VU meters and a popular choice is the LM3914/5/6 series of IC's. You can find may videos of these chips used in videos on YouTube, as an ...
2
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1answer
74 views

Why / how does reactive power help improve voltage quality?

This question is related to my previous question that Olin provided a great answer to. Note that this question is about transmission and distribution systems, not electronics. I believe the claims ...
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4answers
89 views

MiniQuadcopter ESC connection

I have a picture here, sorry if it's ugly .. but let's think, they are my ESCs for my mini-quadcopter. My mini quadcopter is 3d printed, and as much as possible, I don't want to use bullet connectors ...
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6answers
165 views

Why do cables and batteries have a positive and a negative side?

I am a beginner in electronics, mostly self-taught. If electrons are negatively charged and are the reason for electric current why is there a 'positive' side on a battery and negative one? Don't ...
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2answers
71 views

What should I use for a 3.3 voltage reference that sinks maximum of 1mA?

I am in search for stable and precise 3.3 voltage reference IC. I am using it for the temperature sensor application which only sinks 1mA at max. Can someone suggest me a best component/IC for this ...
0
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1answer
57 views

Female Rectangular Headers with Long Pins (Pass-through style)

Female Rectangular Headers with long pins (passthrough style) are used to stack/connect an Arduino shield board to the Arduino board. 1x8 and 1x6 position headers are easily found. Problem: However ...
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1answer
72 views

Protecting a wireless router from voltage fluctuation

Background: I have a wireless router ASUS DSL_N12U. Input voltage and current is 12V , 1.5A respectively. I also have an Inverter (works on three modes: Solar, Battery, Mains) at my home. Problem: ...
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1answer
87 views

Can DC voltage be divided?

I have got an old camera that runs on 7.2V (2 cell li-ion). I only have a 4 cell li-ion battery. Is it possible to divide the voltage without using a DC-AC converter and a transformer? I have looked ...
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3answers
119 views

Convert 0 to -150V DC to 0 to 3.3V

I have a signal that gives spikes up to negative 150V. I need to be able to determine these spikes using MCU that can sens 0 to 3.3V. How can i adjust a signal so that it doesnt fry my MCU. It should ...
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1answer
121 views

Where does 264Vac come from?

Power supplies often accept an input range of 90-264Vac. I am wondering where the 264 comes from. A couple of random examples from power supplies available: 85 - 264 Vac input range (100 - 240 Vac ...
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2answers
83 views

Best way to lower a signal voltage

I'm interacting with a computer and the return high (1) is at 12V but I need it to ~5V. What is the best way to lower the voltage without affecting the signal (serial) ? I already thought of a voltage ...
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1answer
51 views

Battery pack for DSLR coupler

I am planning to make a battery pack, by using rechargable batteries, that i can use to power my DC-coupler for my DSLR camera. (Ref. Image) On my original camera battery it says 7.4V 1.2A but i ...
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6answers
76 views

How do I figure out the exact voltage and current needed for a part?

Whenever I look for parts in my local electronics store, I come across parts(e.g a speaker), that have just a power rating stated(e.g 2W). While I know how to calculate power,voltage, resistance etc, ...
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2answers
259 views

Why does reactive power affect voltage?

Why does reactive power influence the voltage? Suppose you have a (weak) power system with a large reactive load. If you suddenly disconnect the load, you would experience a peak in the voltage. Is ...
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1answer
53 views

12V motor running with 24V L293D H-bridge

I have two 12V motors (300 RPM) running from a L293D H-bridge circuit. I find that the speed when I provide 12V is not satisfactory. Will it damage the 12V motors if I provide 18V or 24V? Will they go ...
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1answer
55 views

Connect two boards together after removing Screw Terminals

An adapter board (to a card edge connector like PCI Express x1) is needed to be designed to for the breakout board below. This should involve replacing the board's screw terminals with some male ...
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2answers
81 views

Watts in Solar Panels

How does the amount of watts affect a solar array? The solar array I found is 14 W, so what would I encounter if I purchased an lower/higher wattage? I'm going to purchase an array to charge my ...
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35 views

DIY Power bank for router? [duplicate]

I'm an electronics enthusiast living in a country with a lot of power cuts, especially through the summer. I want to build a 9V <1A DC power bank for my internet router running on a AC->DC power ...
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1answer
83 views

Buffering Input Signal - Op Amp Alternatives

I need to buffer a 0-5V signal that is coming from a resistor network and being fed into an IC. When I feed it directly to the IC there is a loading effect and the value is changed specifically at 0V ...
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60 views

Voltage Sag with PIC24 PWM Open-Drain Configuration

I'm experiencing some major voltage sag with an open-drain PWM output into an RC servo. I'm pulling up to +5V with an external pull-up resistor. I've tried using everything from a 1k-100kOhm resistor, ...
2
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2answers
111 views

What actually happens in a RC circuit?

I'm currently working my way through a beginner's electronics book(electronics for dummies) where i am introduced to RC circuits as shown in the schematic below. simulate this circuit – ...
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1answer
64 views

How can I create a DC-DC voltage multiplier [duplicate]

I want to take the 5V output from a USB port and make it 12V, so that I can run a cooling fan which is 12V. Is there any circuit I can make at home myself? If the output voltage is not exactly 12V, it ...
0
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1answer
62 views

Measuring voltage output in a voltage divider

I'm currently working my way through Electronics for Dummies, where I am shown a simple voltage divider circuit consisting of a 9V battery and two resistors, R1 (12,000 ohm) and R2 (15,000 ohm). ...
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2answers
177 views

Ohm's Law for voltage divider

I'm currently working my way through electronics for dummies, where I am shown a simple voltage divider circuit comprising of a 6V battery and 2 resistors, R1 (220 ohm) and R2 (1000 ohm) in series. ...
2
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1answer
53 views

Multiple (>2) voltage sources

While working on a schematic for a small development board, I was curious how much work it would be to support an external voltage source (ie. bench-top power supply) in addition to the ICSP header ...
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2answers
129 views

L7805CV won't go higher than 7.5

I am trying to use a STMicroelectronics L7805CV to increase voltage from 7.5v to about 12v, but I can't get it work. I've placed 470 ohm resistors between out and common and between common and ground, ...
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3answers
307 views

Power supply with LM723

I'm trying to troubleshoot a delinquent power supply I have. Most recently one of the transistors (Q1) actually exploded on it. This has led me into investigating the schematic, but try as I might, I ...
4
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1answer
119 views

Help on determining voltage differences (basic circuit theory)

I am trying to reteach myself basic circuit theory using "Practical Electronics for Inventors 3rd Edition" by Scherz and Monk. I am working an example in which it asks to calculate the voltage ...
0
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2answers
118 views

Open circuit voltage

I'm not sure how I go about finding \$V_0\$ in this circuit. The current source just confuses things for me. \$R_1\$ = 10 kOhms and \$I_g\$ = 17 mA in this example.
0
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1answer
51 views

Switching a transistor with audio output

I am wondering how can an audio signal be used to switch a transistor, if the voltage is too low? I am trying to switch some LEDs with the output of an amplifier, but it seems that the audio voltage ...
0
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3answers
86 views

Voltage range shifter from 0V to 3V to -/+1.5V

I'm trying design from scratch (discrete components and opamps) a circuit that could linearly translate from 0V to 3V range to -1.5V to +1.5V. Can someone provide suggestions and designs of how to do ...
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3answers
76 views

How can I extend the ammeter wires to my shunt?

Is it possible for me to locate my ammeter and shunt a few meters away from each other (more than intended by original wiring)? The extra wiring obviously has a resistance and provokes a false ...
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2answers
43 views

Non-parallel, non-sequential circuit

This is the circuit: I've simulated it and got a current of 30.76mA at the voltage source (5V). With this I've calculated the total resistance to be 162.5 Ohm. Each resistors is 100 Ohms big. But ...
0
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1answer
81 views

Analog temperature sensor with 100mV per 1 degree Fahrenheit

My devices only measure analog precision to the nearest 100mV. Most temperature sensors I can find only do 10mV per degree precision. Currently I'm using the LM34. Is there such a thing as an analog ...
0
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1answer
50 views

How to set up a LiPo battery to be able to charge and discharge from the same circuit

I am new to using rechargeable batteries in electronics projects. To give some background on the context of the project, I'm trying to build a solar charger/power pack for a cell phone. My problem is ...