Act of measuring voltage
Voltage is measured using a voltmeter. A microcontroller can also measure voltage using an integrated or external Analog to Digital Converter (ADC).
Questions tagged [voltage-measurement]
885 questions
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Why is the voltage measurement of this circuit different when the switch is on?
I built a simple circuit with two lamps and a slide switch powered by two 1.5 V batteries. When the slide switch is off, the voltage of the circuit measured by a multimeter is 3.15 V:
However, when the slide switch is on, and the lamps are lit, the…
korppu73
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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 no current passing through the voltmeter. I can…
William Tabary-Peterssen
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How do you calculate power loss for a diode?
For example, the DSB20I15PA Schottky diode datasheet mentions a threshold voltage of 0.23V and a slope resistance of 7.2mΩ.
I need to calculate the power loss at different voltages, as the battery drains. e.g. 14V down to 10V.
Is it as simple as…
Nick Bolton
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How does a voltmeter work?
Let's say I've got a circuit with a two-pole Thévenin equivalent that has DC voltage difference U and out-resistance Ro. What does the voltmeter do? I suppose it has an internal, very large resistance (Rv) that is connected in parallel with Ro. But…
Astrid
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What does the moving iron voltmeter measure in a circuit, average voltage or RMS voltage?
What does the moving iron voltmeter measure in a circuit,
average voltage, \$V_{average}\$, or RMS voltage, \$V_{rms} \$?
\$V_{average}=\frac{1}{T}{\int_{0}^{T}vdt} \$
\$V_{rms}=\sqrt{\frac{1}{T}\int_{0}^{T}v^2dt} \$
user6713
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Can't calibrate an analogue voltmeter: Is this normal?
I've just obtained a ALCRON ACROMETER 60 DC 30 V / 3 A panelmeter and have some problems calibrating it.
I plan to use it in a home-made bench power supply and the supply's range is 2.75 V to 35 V. The meter has a zero centering screw and using it…
AndrejaKo
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What does "1000 VRMS CAT II, 2500 Vpk" on a voltage probe label mean?
Our Tektronics voltage probe P5100A has a label of "1000 VRMS CAT II, 2500 Vpk". Could you please tell me exactly what does it mean?
I'm trying to measure an RF generator output voltage which is expected to be about 2 kV in amplitude in maximum at…
Donggyu Jang
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What is the difference between a crest reading volt meter and a peak reading volt meter?
We are measuring pulse DC voltage up to 35K on Tinker & Rasor high voltage holiday meters for checking the thickness of coating applications.
I would like to check our units each time they go out between calibration cycles. We need a peak reading…
Gene Ebbinghaus
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Voltage Divider Circuit
We were doing an experiment on how to get the battery reading. we will be using a resistive voltage divider with a LM741 op-amp and we were wondering what resistor values is the best to use for the r1 and r2 given that our battery source is around…
Soph
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why do digital multimeter show voltage when we touch the probes
Why does the digital volt meter show readings when we touch the probes.. It usually happens when I touch the probes it shows somewhere around 7 to 700mv of values is that natural? If yes.. Then what is the science behind it?
Adil Siddiqui
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Check if an analog voltage is 0
Is is possible to check if an analog voltage is zero (or very close)? If it helps, the input to this circuit will be the output this differential amplifier:
(source: electronicshub.org)
Cart-Cart
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Switching setpoints of a low voltage monitor
I'd like to build a low-voltage monitor that is adjustable by flipping a switch to one of two setpoints. There are plenty of sample circuits, below is one adapted from here
I'd adjust the R2 and R3 to the setpoints I'm interested in, and then use…
Johnny
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Do I need a pulldown resistor with a voltage follower?
As a school project we were given the task to build a remote controlled car. For monitoring the battery voltage, I chose to use a voltage divider with a voltage follower, as the battery has a voltage range of 9.9-12.45 V.
I am also measuring the…
Dominik Koepf
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Accurate measurement of millivolt RMS?
I'm estimating the Vrms of millivolt level (less than a diode drop) sinusoidal signals in the 3 to 30 MHz frequency range, by eye-balling the peak-to-peak height of the sine wave on my 100 MHz oscilloscope and multiplying by sqrt(2)/2 . The voltage…
hotpaw2
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Measuring >40VAC from 230VAC Phase against air
Austrian 230VAC.
I took a DMM and made a voltage measurement between phase and a 5 meter long curled 1.5mm² copper cable with isulation and got a voltage from 40VAC to 100VAC varieing how i curl the cable. The cable is not connected to anything on…
Eggi
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