Act of measuring voltage

learn more… | top users | synonyms

2
votes
2answers
66 views

DC non invasive power measurment

For one of my PhD project I have to measure power consumption from different electric wheelchairs during various tasks and recor these measurment for later studies. I have not much experience in ...
0
votes
0answers
80 views

How to measure microvolts of electricity in plants?

I'm trying to measure electricity in plants, to do something a bit like this: http://www.treehugger.com/culture/organic-electronic-sounds-from-plants-sonic-artist-mileece.html Basically, plants ...
0
votes
3answers
84 views

Measuring a voltage that is higher than your reference voltage

Question: How to measure an input power rail? Let's say I want to build a circuit that switches in a load that draws 1A from a 5V power rail (that is the supply for the device) and then measures that ...
0
votes
2answers
88 views

Need help with fundamental understanding of voltages in this circuit

Looking at the below schematic, with LED1 being a red LED (1.7V forward voltage) and LED2 being a green LED (3.2V forward voltage), I have a few questions that probably reflect lack of some ...
0
votes
2answers
52 views

Digital Voltmeter - TriColor LED Output

I'm very new to electronics and I wanted to start with something that would hopefully simple, but also useful. I'd like to make a circuit that can read a DC input voltage (between 9V and 20V) and ...
0
votes
2answers
57 views

Voltage Doubler stops 'Doubling'?

I constructed a simple voltage doubler on a bread-board. Here's the schematic. simulate this circuit – Schematic created using CircuitLab The output across the 100kΩ resistor was the ...
1
vote
1answer
312 views

What does pseudo-differential mean?

I often read the term pseudo-differential when looking for ADCs. I know common differential means that the ADC measures a difference between two of its pins (AN+, AN-). But what is the difference to ...
0
votes
1answer
35 views

What is the best practice to measure 3 phase grid voltage using a dsp chip for synchronization?

I want to measure the current grid voltage to synchronize a dc power supply with the grid using an inverter. Now I'm particularly interested in finding noise and harmonic information about the grid ...
0
votes
1answer
60 views

ZYNQ ZC702 measurements of current

I need to measure a current with the osciloscope on a ZYNQ ZC 702 board and I do not know what shunt resistor should I pick. I am not so good at electronics so if some one can help me I would be very ...
-1
votes
6answers
90 views

Frequency DC voltage

Maybe it is a silly question, but a microcontroller it is powered up with a voltage of 3.3 DC voltage, and we all know that the frequency of the DC voltage is 0 Hz. Suppose that i want to generate a ...
4
votes
2answers
406 views

ATTINY85 measuring internal voltage

I'm using an ATTINY85 for a portable application that uses a Lithium-ion battery; therefor I need to monitor the battery voltage so I don't kill the battery. Is there a way to go about this without ...
0
votes
4answers
84 views

LED Voltage Drop Confusion

Please take a moment to checkout the simple circuit below: simulate this circuit – Schematic created using CircuitLab As you can see, this is a simple circuit consisting of three LEDs in ...
1
vote
2answers
80 views

Measuring voltage between two points…wirelessly?

I want to measure voltage between points A and B. Let's assume that there's some obstruction/difficulty in simply attaching cables between those points. Is it possible to measure the voltage ...
0
votes
2answers
85 views

Low voltage cutoff circuit

I'm powering an attiny45 from a lithium ion battery; using these batteries the voltage cannot get below 3volts or it will damage the cell. How should I go about cutting the voltage out? Software, or ...
0
votes
5answers
167 views

How measure the voltage over a large resistance?

I know initially this question might come across stupid and obvious but all is not as it seems. I want to measure the voltage drop over a 10M ohm resistor but my voltmeter's probes have an ...
0
votes
5answers
105 views

Why does ammeter or voltmeter measures RMS value

When there's an alternative voltage, why does the voltmeter measures rms value instead of the value at that specific time?
0
votes
1answer
81 views

Why is voltage 0 after the last component in a circuit given electron current flows from negative to positive?

Perhaps a different way to ask my question is why does voltage drop occur on the negative side of a component and not the positive given what is known about electron current? E.g. in the diagram below ...
0
votes
1answer
42 views

dual ramp voltmeter meaningfully displaying the microvolt digit

How can a common dual ramp voltmeter meaningfully display the microvolt digit when measuring a DC voltage ridden by a 50 Hz signal of several millivolts captured from the power distribution network.
1
vote
3answers
204 views

Wheatstone bridge why not use a voltmeter?

I have been reading up on the limitations of a Wheatstone bridge, one of which is that for high bridge resistances any imbalances are hard to detect because of the small current that flows through the ...
1
vote
2answers
275 views

Bench DC power supply output

I recently purchased a ATTEN APS3005D Regulated DC power supply from eBay and I'm having some odd and potentially alarming results that I'm trying to get my head around. Note: I'm testing this ...
1
vote
1answer
90 views

Provide power if power is not present already (circuit inside)

I am designing a simple controller for an automotive application. As you can in the schematic below, they system is consisted of a sensor, a gauge and a controller. This particular sensor shorts its ...
0
votes
1answer
59 views

How to read a wider range of voltages into the SA ADC on a PSoC4?

I want to read in a larger range of voltages into the SA ADC on the PSoC4, however as stated on the data sheet for the ADC component the different modes can only allow a range of 0 to 2 - 3 V and I ...
1
vote
1answer
279 views

How does a smart phone measure the battery power?

A smartphone (assume Android) usually displays the battery percentage from 0 to 100%. I am assuming this is the usable power capacity of the battery. I have several questions: 1) How exactly does it ...
0
votes
1answer
93 views

Measuring the charge of a battery while charging

Determining whether a 12V car battery needs charge is as easy as touching its leads to those of a multimeter. While charging from a vehicle's alternator, the multimeter method fails to determine the ...
0
votes
2answers
321 views

1000 watts, 220 volt, 52" length, Coiled Nichrome wire

I need to use Nichrome wire for heating purposes. My heating temperature could be among 200 Celsius, voltage should be 220V, wattage should be approximately 1000 Watts, and length should be 52 inches ...
21
votes
10answers
3k views

Why can a voltmeter still measure potential difference if it has a (theoretically) infinite resistance?

I am a physics teacher who did engineering and hated all things electrical! Hence when my students sometimes ask me how a voltmeter can measure the potential difference between two points if there is ...
1
vote
2answers
124 views

Why are null measuring methods considered to be very precise?

I heard a professor saying "it's a null method, so it is very precise". He was talking about the force balance pressure measuring method. I think in this cathegory of methods one can include the ...
0
votes
0answers
64 views

pin connection added

I am trying to communicate 24 hall sensor via arduino & 8:1 Mux . I am using CD74HCt4051E 8:1 multiplexer. Instead of hall sensor i have used potentiometer 24 nos and connected to MUX IC devide ...
0
votes
1answer
74 views

Resolution Digital Voltmeter

If I have a 3 and half digital voltmeter operating on the voltage range of 40V then what would be its resolution? While trying to solve this I found in one of the books that only active digits ( which ...
0
votes
2answers
108 views

Series RLC measurement result different with theory

I am measuring the current and voltage in simple RLC circuit: However,the result that I measured show big difference with the simulation result using Multisim. Why is there are a big difference ...
5
votes
1answer
341 views

What causes inaccuracy over time on a DMM?

Here is a piece of information from a datasheet of a DMM. The accuracy rates seemed interesting for me. I wonder what causes difference in the accuracy, especially the changes after 24 hrs? Is it only ...
-1
votes
2answers
72 views

Combining power [closed]

On a computer power supply can I add 12 volts and 5 volts supply to get 17 volt supply? **Edited for clarification
0
votes
1answer
157 views

Single Phase Energy Meter using Atmega32

Version 1 : We are trying to measure the input voltage from the AC mains (which theoretically should be 230 V). The circuit to measure this is a simple resistor divider network as shown below. The ...
0
votes
0answers
136 views

Voltage/current Monitoring - MAX4172 + ADC vs. INA219

I'd like to add some monitoring of voltage and current on the +5V and +3.3V supply rails of a development board power supply. I'm currently debating between two approaches. The first approach is to ...
0
votes
0answers
78 views

Node voltage analysis of PMOS charge pump

Why is it that the voltages at nodes A and B are 3.7 V and 7.4 V respectively at a certain phase, i.e phase 1? And just the ...
1
vote
1answer
86 views

Measure battery voltage

For a LiPoly-accu driven device using the Olimexino-32u4 board (includes LiPoly charger) I want to measure the accu state (voltage?). How to measure the voltage without the need for a current ...
1
vote
4answers
126 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 ...
2
votes
3answers
3k views

Why does an oscilloscope show a different voltage from a signal generator?`

I have a Rigol DS1052E oscilloscope and a Rigol DG1022 function generator. I have just changed the oscilloscope fan for a silent one, as I found, as is commonly reported, that the original fan noise ...
0
votes
1answer
76 views

Modifying a chip on a bought voltage measurer

I have bought a battery checker for my RC LiPo battery packs. The battery checker can measure and alarm at low voltages between 2.7 and 3.8 volts, however with LiPo batteries, the interesting range is ...
-1
votes
2answers
1k views

RMS vs DC(mean value) when calculating power of pulsed or rectified signals

When I have either a rectified signal (like the unfiltered rectified sine wave out of a diode bridge) or say a fast pulsed signal feeding a LED and resistor, in which both the DC component and the RMS ...
-1
votes
1answer
109 views

Frequency modulated voltage measurement with VFC voltage to frequency converter and counter

I would like to measure the voltage across a nonlinear high voltage pulsed power circuit. The pulse is an underdamped RLC discharge but with some non linearity in the inductance. A quarter cycle is ...
0
votes
2answers
448 views

How to measure microvolts of biopotential with Arduino?

I'm new to electronics, so don't judge me harshly. I need to measure the biopotential of a human. I will place special electrodes on the skin, and need to measure the voltage on it. Ordinarily, the ...
1
vote
2answers
58 views

How do I measure time delay from power ON to console messages

I am working on Microzed board (schematic is here). User guide is here I want to measure time elapsed right from Power ON to first message that comes on the console. The message on cosole comes ...
3
votes
1answer
124 views

Backward measurement of AVcc against reference voltage connected to ADC input

what you think about ADC backward measuring supply voltage in microcontroller? It looks interesting for battery-powered devices. The idea is: Connect constant voltage (some voltage reference IC) to ...
1
vote
2answers
156 views

Broken phono pre-amp, is op-amp bad?

The left channel of a phono input on a mixer is outputting only noise. It is measuring -8V DC across input terminals, while the other channel is measuring 0V. The dual op-amp, a 4580, is getting ~27V ...
0
votes
2answers
72 views

What is the function of the voltage meter in this circuit?

simulate this circuit – Schematic created using CircuitLab See the above schematic. I don't know if it's 100% correct, because it's my first time using it and some of the symbols are ...
1
vote
1answer
268 views

Nodal analysis independent and dependent voltage source and current source

After spending quite a few hours I am stumped with this problem while trying to solve for Vo, which is supposed to 0.5V and this was confirmed through PSpice. I have no idea what I am doing wrong or ...
0
votes
1answer
88 views

What is the distortion introduced by a multiplexer?

Question in short: If I have a multiplexer, and my selected input is X volts, I suppose that the multiplexer's output will be X+-ΔX volts. How can I calculate ΔX ? Question with more details: I ...
0
votes
1answer
304 views

Circuit to provide 0-5 V output proportional to 0-30 A from C.T?

I want to design a circuit to protect oveload current of 30A.I have a controller board(PLC) which accepts the voltage range of 0-5 as an input and C.T with 1:7000 turns which can maesure 0.5 -60 ...
2
votes
2answers
234 views

Understanding crest factor of a voltmeter

I was studying signals and systems and came across the crest factor which is defined as the ratio of Vmax of the signal to the rms value of the voltage with the dc component removed. It then proceeds ...