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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Maximum input voltage so that no clipping occurs

Suppose we have a combination (dual) clipper circuit with two diodes. What is the maximum input voltage width so that no clipping occurs at all? Is it 0V because in any case at least a really small ...
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33 views

Can different sources with same voltage output can drive different amount of current through the circuit

I started experimenting with electronic devices. While I was doing that I connected a DC motor to output of arduino which provides 5V. It could not provide enough amount of current. But when I ...
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3answers
95 views

Voltage current relationship

I'm studying cert 3 in Electrotechnology as an electrical apprentice. My tafe lecturer is insisting that in an ac circuit, and increase in voltage will cause a decrease in current. I'm aware that it ...
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3answers
78 views

How does a constant current (CC) power supply regulate voltage (V) in parallel circuits?

I see that some power supplies provide a wide range of output voltages meanwhile maintaining the current. For example: 2.7 A, 20-36 V output. I understand that the voltage rate will depend on the ...
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39 views

cmos inverter in voltage regulation

How does a CMOS Inverter drives the gate of MOSFET for voltage regulation? I have attached the image for clarification. I just want someone to explain me why two cmos inverters are connected to the ...
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37 views

Voltage regulation for HDD

I want to put together backed up power supply for diy NAS. The ARM development board accepts 12V and draws max 1A, no info on voltage it accepts. The HDD is Samsung HD154UI, specs say it draws max 2A ...
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44 views

Does changing voltage modify crystal frequency?

The crystal (16MHz) is connected to an ATMEGA328P-AU which I usually power at 5V, so I presume the frequency it supplies is of about 16MHz. Does the frequency of the crystal change if I power the ...
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1answer
25 views

How to change component values when changing tube B+ voltage

I'm starting a build a tube headphone amp from diyaudioprojects.com (the simple one: http://diyaudioprojects.com/Solid/12AU7-IRF510-LM317-Headamp/) The projects uses a 12V supply for the tube plate ...
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46 views

Why is current going towards the voltage source in this circuit?

You can see that Is was labeled as going towards the voltage source when doing KCL at node a. Can someone tell me why? Is it not supposed to go into the node?
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2answers
58 views

2.8V UART to 5V MCU - how?

I'm trying to connect ZTE MG2639 to 5V AVR (or USB<->RS232). This module is using 2.8V at IO. How can I do that? Normal voltage divider? And how to check if communication is OK in Putty? Just type ...
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3answers
96 views

Why LED reversed bias voltage cannot be measured?

As I have just found out, typical LED does not behave similarly to standard diode when measuring reversed bias voltage. On typical diode, you can measure reverse bias voltage about .3 to .6V, but not ...
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73 views

I'm looking for a way to amplify voltage

I'm working on a project that takes a PPM signal generated from a PC and sends it into radio control transmitter. Unfortunately the radio is not receiving the signal. I asked around the ...
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40 views

problem with dc battery source

I have a dc 9v battery which gives 8.66 volts reading when measured by a multimeter. When I connect the battery to a breadboard, without any circuitry attached within the breadboard, the reading is ...
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1answer
101 views

Second-Order RLC Circuit

How do I find the second-order differential equation, in terms of \$i(t)\$? At time \$t>0\$, the voltage source will be gone, and I will have a parallel \$RLC\$. I am having problems with finding ...
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1answer
57 views

How to picture sinusioidal wave in transmission line(electrical circuit in general) ?

I have a friend who keeps asking how does a sine wave flow in transmission line. I've tried explaning him that it is the folw of charges in either directions but he isn't convinced yet . Can somebody ...
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1answer
84 views

How does underdriving a powerful (eg. 50w, 100w) LED chip work?

My question concerns under driving an LED chip. Unlike quality brand chips (Bridgelux, Cree), in my experience, under-driving non-brand ones make things more long lasting and favorable. Using the ...
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1answer
95 views

How can I store energy from short pulses of current?

BACKGROUND: I am an intern with a local company. We have a powerful 60 KW Engine that runs throughout the day. We have a two Machineries that are powered off the Engine directly (using clutches and ...
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2answers
48 views

Best resistance for RED/BLUE 3 lead LED

I have a project where a PCB has been manufactured with an error, where a 3 lead BI color LED (red/blue) has a single resistor to limit the current for both colors. I can fix this by hacking apart the ...
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2answers
176 views

Determining the voltage and charges across each capacitor

Since someone edited my question and asked me to post a new question instead with the edits I did, so here is the new schematic for this question: Can someone help me find the voltage and charge ...
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4answers
63 views

Unknown voltage in IR pulse sensor circuit

I've build a simple circuit based on the sketch from here: http://makezine.com/projects/ir-pulse-sensor/ simulate this circuit – Schematic created using CircuitLab However, after ...
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2answers
47 views

Relay - Datasheet Max DC Voltage

This may seem like a dumb question, but I want to be sure. In the below datasheet, what is the DC voltage the relay can handle? I am assuming it is the ...
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1answer
38 views

Arduino analog input higher than reference but lower than 5v [duplicate]

I'm going to use a very precise potentiometer that can measure angles from 0 to 3600 degrees (10 rounds), but I only need the first 180 degrees or so in this project and I need it to be more precise ...
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2answers
65 views

What Does Rated Load of a Tactile Switch Mean?

I want to connect a tactile switch to an GPIO pin of MSP430 (which runs on 3.3 volts). The datasheet of the micro-controller says that IO pins can withstand max current of 6mA. The tactile switch I ...
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2answers
69 views

Controlling an electric motor through labview without knowing its speed

I'm having a little trouble running my final bachelor experiment. My group and I are to find out what exactly causes extreme high frictional forces when pulling a steel cable through wet sand by ...
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1answer
88 views

What is the difference between Vio and Vcc in an electronic circuit?

Can someone please explain the difference between Vio & Vcc and what do they stand for ? Edit: Modified my question based on the first comment.
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3answers
248 views

What is the test voltage of a ohmmeter?

Ohmmeters don't appear to make LEDs conduct which gives overestimates in the resistance measured (tested with a R1//(R2+LED) parallel circuit). So what is the voltage they apply to the circuit, ...
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1answer
32 views

Replace a Solar Panel with a charging brick

I have a small solar lamp with a messed up solar panel. Now i want to replace the solar panel with a charging brick in order to charge my lamp. The question is what specification of charging brick ...
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2answers
54 views

Connecting two motors

Basically i'm doing a small project where i'm using 2 dc motors on a bicycle as generators connected to a usb module to charge smart phones, is it possible to connect the motors together to generate ...
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4answers
157 views

230 and 240 transformer leads

So I have a transformer that is like 230 || 30 V. One thing I don't get that on primary side it has the following leads: 0 --- 230V --- 240V When it can be useful? I mean I can't think of situation ...
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2answers
304 views

Does an electrocardiography recorder put current/voltage on its electrodes?

(I do hope my question is not off-topic) Currently learning about ECG recorders (Our 7-months old daughter has to have one during her sleep), I wonder whether this is a pure "passive" measuring ...
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1answer
42 views

Microcontroller GPIO input voltage limit

I was looking at a datasheet for a microcontroller and noticed that, under its section for GPIO input voltage (p.14), there is no listed maximum for the high input, only a minimum. Does this indicate ...
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3answers
121 views

What happens if I supply a higher voltage than the rated voltage of my jack?

I want to replace the original jack from my notebook with a new one since it is broken (and I would like to avoid to replace it with the same as the original). The original AC adapter supplies 19V and ...
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1answer
92 views

Why are these Vias of Different Shapes

While looking at how other circuits bring AC mains into their circuits, I came across this design where there are 3 differently shaped vias (from top to bottom): Figure of ...
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56 views

Darlington Transistors ULN2003APG Base Voltage

I want to control a 30x1 array of pins through a raspberry pi B+. On a breadboard, I set up a series of shift registers (74HC595) to an array of 2V leds, which I can control as intended. After the ...
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73 views

Problem simulating a fixed transconductor with LTSpice

I am simulating a fixed transconductor circuit with LTSpice. When I apply \$1\$V for input voltage, (for DC Sweep) the voltage of collector of \$Q_1\$ has good amplitude (\$30\$mV to \$330\$mV) while ...
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2answers
130 views

Finding the voltage and charge across capacitor

Can someone help me find the voltage and charge across each of the capacitors? This is not just a simple/ parallel circuit so I am having a problem in formulating the right equation on how to find the ...
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1answer
97 views

Induced EMF of different wire shapes?

Given the following diagram: Both conductors are moving at the same velocity, and the same direction, and are in the same magnetic field. They should induce the same ϵ even when their shapes are ...
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0answers
24 views

How to calibrate pico-ammeter votage bias?

I'm using Keithley 6487 pico-ammeter. It's strange when I turn on the machine without connecting any circuit, there exists 0.05 Volts difference between the in and out probe. So I have to add -0.05 ...
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2answers
77 views

Voltage regulator lm78xx for 220v?

I can see that the input voltage of the lm78xx series is 30-40v dc . We are looking for a voltage regulators system , that will get the 220v ac , and turn it into a : 3.3v, 12v, 24v, dc . I was ...
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1answer
23 views

how to convert synchronous generator field voltage from per unit to voltge

I've been working in PSCAD and in this time I'm struggling with synchronous generator in PSCAD. As you know synchronous generator in PSCAD, working in per unite so I have to change its amount to ...
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1answer
33 views

Capacitor Units For Power Factor Correction

I have got the assignment to improve power factor of an industry. I have worked it out and found capacitance in K Vars and Micro Farads but need to know about the capacitor representation in volts?
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1answer
55 views

Feeding arduino with AC?

Im having trouble trying to understqnd this circuit , as you can see from http://www.instructables.com/id/Arduino-Audio-Input/?ALLSTEPS its a circuit that will amplify a signal from 200mV to 2.5V and ...
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2answers
101 views

Induced EMF without motion?

I have a fixed wire and an electromagnet next to each other, and would like to induce continuous \$\epsilon\$ from the change of \$B\$ or \$A\$. Currently I'm focusing on changing the magnetic field, ...
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1answer
98 views

Can a simple voltage divider circuit be used to accurately measure voltage?

I have a discharger circuit that I intend to hook up to a 3V battery. Total resistance of the circuit (depending on how fast I intend to discharge it) will vary from 0.04 to 0.01 Ohms (that's 75A and ...
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2answers
133 views

Controlling a 12v potentiometer with Arduino

I want to use an Arduino to control a motor I pulled from a treadmill. The treadmill came with an MC-60 controller. The treadmill used a potentiometer to control the motor speed. Here's a portion of a ...
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1answer
106 views

Choosing N-channel MOSFET for 12V output [on hold]

I'm looking for an alternative to the STP16NF06L MOSFET N-Ch 60 Volt 16 Amp as Radioshack does not carry it. The MOSFET is meant to take a 5V PWM signal from the Arduino to drive a 12V LED strip. ...
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4answers
296 views

what could be the visualization equivalent of the resistors in series?

Why do resistors in series add-up? Is there any visualization equivalent of that? I have in mind electrons as cars driving on the highway, now a resistor could be a narrow spot (R1) where cars are ...
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1answer
53 views

DC Motor Coil Voltage

I have a DC stepper motor that appears to be powered by 75V supply voltage (I measured this). However after connecting the motor to the controller (supply), I measured the voltage across the coil ...
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2answers
99 views

If voltage can exist while current is 0…?

In the following diagram voltage can exist without current since it's an open circuit: simulate this circuit – Schematic created using CircuitLab Can a voltage source in an open circuit ...
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1answer
56 views

Arduino not driving RGB LED Strip

I'm using Arduino Uno with a 12V RGB Signal Amplifier and a 12V RGB LED strip. 12VDC is supplied to the amplifier. However the LED strips does not light up whether the PWN pins are set to either ...