Act of measuring voltage

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52 views

Strange frequency of audio output voltage

For a school science experiment, we have stripped an audio cable and hooked the right channel and ground wires up to a voltage graphing device. The audio cable is plugged into the audio output of our ...
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2answers
44 views

Why we want to convert a voltmeter to an ammeter or vice versa?

Why in laboratory experiments do we want to convert a voltmeter to an ammeter and vice versa? What is our main aim here that is for what we are doing it? If our goal was to change the range of the ...
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2answers
86 views

Getting negative voltage reading when negative voltage does not exist. Why?

I am beginner trying to make sense of some weird voltage readings I am getting. Please take a minute to look at the circuit below: If I take my oscilloscope and capture the voltage activity across ...
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1answer
41 views

Which bypass cap position creates a cleaner voltage and current feedback circuit?

Is the following true? Caps = 2, 1800 uF Nichicon, Manf Num UHE1V182MHD3, CAP ALUM 1800UF 20% 35V RADIAL. "you want your bypass caps as close to what you are bypassing with the least series ...
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3answers
69 views

How to measure H-Bridge motor voltage using ADC

I am controlling two motors using a double H-bridge controller. I would like to measure the voltage at each motor using ADC's on the microcontroller. The problem is that the motor voltage may be ...
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1answer
34 views

Expected repeatability of PT100 temperature sensor

I'm designing a circuit to measure temperature using a PT100 sensor. I'm putting 1mA through the sensor, and measuring the voltage drop. Assuming a perfect voltage measurement, what would be the ...
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1answer
120 views

Measuring an analogue voltage with isolated ground

I am working with a solar EV (car), and I need to measure the throttle pedal signal. The throttle peddle is essentially a 10k ohm pot between 5v and gnd on the motor controller. (0-5V signal). As ...
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0answers
35 views

Unknown voltage oscillations in sensor data acquired by NI 9234 DAq module.

I am using a National Instruments 9234 Data Acquisition module for the measurement of voltage across my pressure sensor which is used to sense the pressure on it by measuring the voltage across it. ...
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1answer
46 views

How to properly measure voltage of external supply

What is the proper way to measure an external supply like a 9V battery which is not connected to the controlling part (micro-controller) of the system. Take an external 1-Channel SAR ADC with SPI ...
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1answer
81 views

How to make Current to Voltage converter [duplicate]

I am working on level sensor which give output of 4-20 mA. I have to feed output of level sensor to an ADC of a micro-controller, to do so I have to convert it from current to voltage.Voltage range ...
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2answers
63 views

How can I collect data from a hydrophone?

I want to collect data from a hydrophone over a period of days or weeks. Hydrophones are a piezo-electric transducer that output millivolts (thousandths of a volt). A response from a hydrophone might ...
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1answer
62 views

Voltage measurement

With the 100ohm resistor sitting between my 12V power supply and my device it doesn't spin (it's a hard disk). I also tried to measure the voltage drop with a multimeter to no avail. It always shows ...
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3answers
64 views

Effect of 2-terminal and 3-terminal Voltmeters and Arduino Voltage Sensing on Circuit

I am trying to build a board to sense circuit voltage relative to ground at different points on a breadboard. I would want the board to work regardless of configuration of the circuit. The only ...
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0answers
31 views

3 channel vs. 4 channel 120/240 power meter

So I live in the US, where we have center tapped power for residential use, with two hots and a single neutral wire. My question is what would be the potential effective difference in power ...
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3answers
127 views

Cross-talk in an RGB photodiode circuit

I'm trying to make an accurate RGB detector, where the R,G, and B components of a sample are measured via the voltages $$V_R, V_G, ~\text{and}~V_B,~\text{defined in the following circuit:}$$ Where ...
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1answer
80 views

how can we measure the voltage upto 2000V [closed]

i m having the voltage measurement device of 1000 V. but i have to measure voltage of 2000 V. what are the techniques that can be used to measure this voltage?
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1answer
61 views

A possible decimal digit dvm?

I would like to build a 3x10 decimal digit dvm for an edge lit numerical display. The nearest schematic that I can find is using a CA3162E / LM74LS147 which can be found at: ...
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1answer
63 views

Measuring 60 Hz AC from a piece of wire

I am trying to measure the presence 60 Hz AC signals using various shapes of wire antennas. I will be sending the voltage present on these antennas into a high impedance op amp stage. But before I do ...
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4answers
179 views

How would you solve this resistive network?

simulate this circuit – Schematic created using CircuitLab I'm not really sure how to solve this. I can't see any series or parallel connections. I need to find the Total resistance, V1 ...
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1answer
73 views

LED DC Voltage Level Indicator

I am wanting an at a glance indicator of what voltage level is being supplied by a DC generator (think pedal power). My general thought is a series of LEDs that light up in sequence as the input ...
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2answers
62 views

Input-output voltage vs needed voltage [closed]

I want to use a new modem-router to replace one fried by a power surge. Snake-bit by that, I checked out the voltage for the new unit's adapter. It's supposed to be 12V, 600ma. Using a ...
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2answers
126 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 ...
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0answers
132 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 ...
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3answers
148 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 ...
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2answers
93 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 ...
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2answers
79 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 ...
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2answers
97 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 ...
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1answer
422 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 ...
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1answer
79 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 ...
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1answer
80 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 ...
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6answers
137 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
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2answers
826 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 ...
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4answers
118 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 ...
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2answers
105 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 ...
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2answers
162 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 ...
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5answers
229 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 ...
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5answers
327 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?
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1answer
90 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 ...
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1answer
53 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.
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3answers
476 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 ...
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2answers
389 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 ...
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1answer
129 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
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1answer
80 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 ...
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1answer
1k 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 ...
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1answer
154 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 ...
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2answers
675 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 ...
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10answers
4k 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 ...
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2answers
229 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 ...
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72 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 ...
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1answer
185 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 ...