Questions tagged [voltage-measurement]

Act of measuring voltage

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7
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5answers
3k views

What does the horizontal bar indicate in the DMM display?

What does the horizontal bar indicate and how to use it in my measurement?
0
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1answer
15 views

Right settings for the voltage ripple measurement?

Background: I have been assigned to monitor the signals related to TPS61091 boost regulator section. I am particularly keen with respect measuring the ripple on the 3.3 V output voltage. I have Lecroy ...
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2answers
53 views

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 ...
1
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1answer
54 views

Measuring 150kHz, ~30V peak waveform with good resolution

I am trying to choose test equipment for a systems test application and I am running into a road block with one of the specs I need to meet. The device features an H-bridge output similar to the ...
1
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3answers
80 views

How to raise voltage output of charge controller IC due to cable loss?

I am using a CN3703 IC to charge a 3 cell li-ion pack (layout as below.) The charge current is programmed using a resistor between its CSP and BAT pins which develops a voltage drop of 200mV. The ...
0
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1answer
31 views

Lumped model not applying to PCBs

Recently I have heard that KCL and KVL do not fully apply when performing electrical measurement on PCB traces. It was implied that PCBs are not completely lumped circuits - that is, we cannot assume ...
0
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0answers
26 views

Low power LiPo cell ADC with an nMOS switch and a resistor or capacitor divider circuit?

This is my first question on this platform and am looking for advice on doing a very low power LiPo battery measurement for a wearable device. My current circuit looks like this: (See image below) ...
1
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2answers
56 views

High voltage coaxial probe measurements

I am designing a high voltage motor controller and I want to validate the switching circuitry to ensure there's no excessive ringing behavior. I had an idea to use something like an SMA or u.FL ...
1
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2answers
56 views

Connecting DC Common Node (Ground) to Three Phase Neutral

I know I shouldn't. But I just wanted to ask due to a specific requirement. I also searched the forum but couldn't find any similar question. Please give me a link if there's any. I'm asked to modify ...
0
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2answers
38 views

How to show that voltages on diagram are 120° apart?

So i'm doing a matlab simulation of delta wye transformer and would need to show the phase shift between voltages. Here is a picture of input voltages so how would I show on this graph mathematically ...
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2answers
54 views

How can chassis ground be used for voltage measurements in a device with components of differing voltages?

The manual for my HV probe tells me to connect my ground clip to the chassis. I can see how this would be good advice for say a 12V car, because the chassis is made the ground and every component uses ...
3
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0answers
82 views

Replacing an ammeter with voltmeter?

I have found this circuit of a millivoltmeter, and it seems like something which as a hobbyist I can do it, and the range of the measurement is very suiting one of my projects, but I would like to ...
1
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1answer
96 views

AC Nanovoltmeter for Arduino alike?

I have searched across web, but I am unable to find such a circuit. I am looking for a circuit of a AC nano-voltmeter in range 5-10 to 100 nV which output is suitable to be handled by some precise ...
1
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1answer
69 views

Voltage and Current Sensor for Alternating Current

I want to measure the voltage and current of a AC powered device using a micro controller like Arduino. I am unable to find it.(I am new to these). Is there a circuit or sensor which isolates from the ...
0
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3answers
51 views

how can I calculate the smallest measurable voltage for a given adc?

I have a project where I use 4 strain gauges in full bridge configuration with a hx711 module and an Arduino mini pro. How can I estimate the smallest voltage I can measure with a given adc from its ...
1
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0answers
85 views

Auto Scaling in a Multimeter

I’m trying to create a multimeter, I’ll be mainly using a 16 bit ADC (ADS1115), an ESP8266 on Node MCU, I’ll use the MCU to communicate with a phone app to switch between different multimeter modes, i....
1
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0answers
55 views

Measuring just half the sine wave of a current measuring transformer?

I'd like to measure current of electrical devices using one of those split-core transformers you clip around an AC wire, which has a built in shunt resistor and hence outputs a voltage. I'd like to to ...
3
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2answers
60 views

How to measure the output impedance of a Zener diode in avalanche?

I'm trying to measure (on the bench) the output impedance of this:- simulate this circuit – Schematic created using CircuitLab It's a Zener diode, and the applied voltage is sufficient to ...
0
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1answer
56 views

Compare tiny capacitance using comparator [duplicate]

I want to compare the capacitance of two tiny capacitors at around 10^-15 F each. One will change compared to the other by at maximum factor 3. I need to measure the relative difference between them ...
3
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4answers
2k views

Measuring voltage across 1 ohm resistor

This might be a very stupid question, but I can't seem to figure this out and I'm going nuts thinking about it. Assuming you are trying to adjust the fixed bias of a tetrode push pull pair in a tube ...
0
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1answer
40 views

Advice on a voltage measuring circuit

I've been working on a voltage divider circuit that will hopefully allow me to measure voltages between 0-60 kV DC (80 W) as 0-889 volts DC. The voltage divider section that is used to measure the ...
0
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0answers
36 views

How to find current and voltage of a certain appliance connected to an outlet?

Objective: I'm new to electricity and trying to convert my mirror integrated with LED work with a power bank. I need to find how much voltage and current is needed to make it work. How can I measure ...
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2answers
46 views

Explanation for Method of Monitoring Current from a Power Supply

I recently came across an interesting way to monitor current, but was not certain exactly how it works. Likewise, I was hoping that someone might be able to explain how the device measures current. ...
0
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1answer
41 views

Simple voltage presence monitoring with negative power supply

I am switching a 230-240 V load with a TRIAC and relay while also monitoring the presence of voltage on both ends of the load (i.e. not measuring the amplitude -- just that the switch successfully ...
2
votes
2answers
93 views

LT1510 as a CC and CV Battery charger

LT1510 is a battery charger IC that can be configured to charge any kind of battery pack, I am interrested about the circuit given in the application note referenced AN68F page 24/36. The IC is used a ...
1
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1answer
54 views

Measuring Output Ripple Voltage

Please check the below waveform of my 5V output ripple of the buck converter. I am measuring the output ripple across the output capacitor of the converter. Why are these spikes coming while ...
1
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2answers
68 views

Voltage divider resistor PN balancing

Refer the representational schematics for voltage sensing by ADC (SAR). I read somewhere to balance the P and N lines add R3 = R1||R2. How come R1 and R2 parallel combination could be considered as ...
1
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1answer
236 views

acs71020 Connecting and reading voltage properly

I am using an ACS71020 3.3V I2C version hooked up to ESP32. I have connected the IC as proposed in the datasheet. Rsense used is 1.8k ohm as proposed in the evaluation board user manual for 230-240 ...
1
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2answers
43 views

Measuring output voltage (Single ended probe vs differential ended probe)

I have a SMPS buck 3.3V output. I am trying to measure the output voltage at the output capcacitor using Oscilloscope. I am using a single ended probe with spring ground tip to measure the output ...
0
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2answers
30 views

Effect of the horizontal magnifier control on the sweep speed, sweep time and number of cycles observed?

What is the effect of the horizontal magnifier control on the sweep speed, sweep time and number of cycles observed? Sweep speed increases by ten times for a 10X magnifier, sweep time reduces by the ...
0
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1answer
50 views

Measuring Voltage drop across MOSFET 2N7000

My setup is 2.1V on the gate. A 330 Ohm load between Vdd and drain. And Source to ground. I stepped Vdd from 0V to 9V in small increments and measured the current through Vdd to ground. Got currents ...
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0answers
29 views

AC Measurements: Level Shifter vs Negative Voltage Supply

I’m trying to design a circuit capable of measuring AC signals with a high level of accuracy. The two most popular options I’ve seen so far are: a) Supplying the ADC with a negative ground supply (2....
0
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2answers
40 views

Use single-pole voltage detector to check for currentflow on a lamp

I am using a single-pole voltage detector to detect if there is a current-flow / potential on the clamps of my ceiling lamp (See device in first picture below). When the ceiling-lamp is ON and ...
0
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1answer
117 views

INA219 bus voltage depends on supply voltage

I tried to measure voltage with INA219A connected to Arduino. As datasheet says INA219 works from 3V to 5.5V supply voltage but I get different values for bus voltage when I change supply voltage. ...
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0answers
31 views

Temperature coefficient of a voltage source

Is the temperature coefficient of a voltage source related to the internal resistance of the voltage source? Why does the voltage increase/decrease when the temperature is increased or decreased? In ...
1
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2answers
94 views

touch sensor for metal door handle

I was thinking if a current is applied to a metal door handled and somebody touched it that should complete the circuit to ground and be detectable but I'm not sure if this would work as the 'somebody'...
0
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1answer
41 views

How to find out the maximum current across a voltage source(using a DMM)?

I have an old Nokia phone charger lying around which I want to adapt for powering my breadboard/PCBs. I was trying to find out how much current the charger was able to supply, so I connected a DMM ...
0
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0answers
26 views

Battery monitoring using voltage divider circuit using 4 resistor

I want to measure the battery voltage using voltage divider on different ADC channel, as shown in image i have to used 4 resistor and generate 3V, 2V, and 1V from 4V battery. i want to measure all ...
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0answers
10 views

Insertion loss measurements, frequency sweep vs measuring points with a constant driving frequency

I have been modelling a surface acoustic wave delay line, and am trying to clarify what I am seeing in the different models and whether this is applicable to what would occur experimentally. In the ...
1
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1answer
67 views

Contact potential between metals

Metals Al and Au are connected in series. An ideal voltmeter, with both of its leads made of Cu, is connected across them. Then how come the voltmeter gives zero reading but why can't we measure ...
2
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5answers
2k views

Does an oscilloscope subtract voltages as phasors?

I want to measure two voltages on an oscilloscope. They are not in phase. I want to know the magnitude of the voltage difference. The oscilloscope has an in-build math function to subtract the ...
1
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0answers
30 views

How do I measure the fluctuation of a pulsed voltage of ~1700V?

The problem: See the little sketch. Starting from a high-precision DC power supply, I pass the voltage to low-pass filter and a pulser. This pulser pulses the nominal voltage of around ~1700V down to ...
0
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1answer
95 views

LM339 Lipo Battery Voltage Tester Circuit - How does it work?

After reviewing the eevblog video on OpAmps and various other videos on the LM339, as well as copying a circuit which works, I am still genuinely confused on the math / logic behind this, which makes ...
0
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1answer
51 views

Help finding voltage between two points

So, how should I proceed to find U_ab (or V_ab)? I have found I = -0.5mA, U_1=-2.5V, U_2 = -0.5V, U_3 = 2.0V. How would I even find U_a and U_b separately so I can apply U_ab = U_a - U_b? Also, ...
1
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1answer
188 views

Useless pins in HDMI cable?

In order to connect two small electrical circuits, I needed 17 pins. Because of its availability and compact form, I chose the HDMI connector. The two circuits are connected using an HDMI cable that ...
0
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0answers
27 views

How can I convert FMCDAQ2 Analog Devices Data Acquisition board from AC-Couple to DC-Couple input?

This is a Data Acquisition FPGA board from Analog Devices: https://wiki.analog.com/resources/eval/user-guides/ad-fmcdaq2-ebz/hardware#picture_and_main_components We have to use this card in a project ...
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0answers
28 views

Fluke 322 clamp meter

My meter will read 11 to 14 ohms when leads are touched together. When trying to read AC or DC voltage with leads or clamp I get no reading at all? I did remove batteries and took the unit apart ...
1
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1answer
114 views

Measuring battery voltage and impedance

I have been trying to figure out how to properly measure battery voltage for a few days. The more I read, the less I understand. I know there are many questions like this out in the internet and I ...
1
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0answers
79 views

What do these capacitor markings mean?

Aluminum Organic Polymer Capacitor So to be really honest, I did blow an capacitor a while back by applying the wrong voltage to it, and had ever since then trying to decode this info to track down an ...
0
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2answers
121 views

Why doesn’t voltage drop to 0 when a capacitor becomes fully charged?

This is my understanding so far of what capacitors are and how they work, if it helps to answer my question at a level I can understand: A capacitor is composed of two equally sized conductive plates ...

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