Questions tagged [voltage-measurement]

Act of measuring voltage

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46 views

Op Amp for DC Voltage Measurement

I'd like to measure 0-800VDC using the ADC of a PIC18F and opto-isolated from the high voltage. Since optocoupler's CTR is variable and non-linear, I'll use the IL300. Checking this application note, ...
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1answer
38 views

What opamp configuration to choose to measure 1kHz square wave with 1MHz signal modulated on it

I have 1kHz square wave I would like to measure the max and min voltage of. But, it is asymmetrical in both amplitude and duty cycle and it has a 1MHz 1V signal on it. The input impedance should be > ...
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3answers
74 views

DC/DC system has voltage between grounds

My system is powered by 60 V battery. First converter is 60 V / 12 V isolated, second converter is 60 V / 12 V non-isolated. Two converters power own system component. When I measure the voltage ...
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2answers
39 views

Measuring a 2-pin active wheel speed sensor without having it connected to a vehicle

I'm trying to measure/test the square wave output of an active wheel speed sensor from a jeep wrangler for a project I'm working on. I do not have access to the actual vehicle just the sensor itself ...
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3answers
69 views

Why would a large resistor in series cause a different voltage reading?

I'm watching Electroboom and don't understand why the voltage drops when he touches the spoon. He states there must be a large resistance in series. Why would the voltage not already have dropped ...
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2answers
73 views

Express reverse diode voltage drop as a function of temperature

I've made a simple temperature meter, with means of series of Ge diodes, followed by 10k resistor. I am applying +5V to topmost diode cathode, and measuring voltage drop between resistor and ground ...
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1answer
39 views

AS8510 ADC Reading to Current/Voltage Measurement

I have this AMS AS8510 data acquisition IC for battery management with dual ADC (datasheet) that is supposed to measure the current, voltage and/or temperature of a 12 V battery. I'm having a hard ...
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1answer
41 views

Correct way to measure a 4-20mA sensor?

I have an 0-10V analog input channel that I would also like to measure 4-20mA sensors. I have added a 500 ohm shunt resistor I can jumper in when I am using the 4-20mA instead of the 0-10. Can this be ...
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1answer
43 views

How to change Voltage Reference in STM32 NUCLEO-F103RB board Analog Input from 3.3V to 5V?

I have a joystick module for Arduino connected to my PA0 pin (that pin is set as ADC1_IN0). I would like to read the voltage from that pin but there is a problem. The voltage on which the joy-stick ...
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1answer
27 views

Reading and writing analog voltages to two outputs of a lab bench supply from one microcontroller

I am planning on building my own lab bench power supply which should be software controlled and have two outputs. I am considering using the ATMega2560 due to its large amount of I/O pins, but I don't ...
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1answer
56 views

Calculate Voltage Seen at High Impedance Pin

Background I am designing a simple lamp dimmer circuit for use with a 450W bulb for the purpose of heat fusing various synthetic materials. I have the basic dimming functional but now I am ...
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2answers
36 views

Adding Hysteresis to Supply Voltage Supervisor

I am going through this TI-APP note - Voltage Supervisor,with hysteresis. I am not able to understand WHY they have derived the below equation 1 & equation 2 in the App note (page 2 & page 3)...
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2answers
47 views

Circuit with dependent & independent voltage sources - Why not matching?

I've just solved this exercise by hand and then I have compared the results with PSIM Simulator and there's a difference of e-006 in the Voltage Vo. I just can't understand where's the mistake, I have ...
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0answers
52 views

How does a voltmeter measure the voltage of a PWM signal?

I have a DC / DC converter in the + -12V output connected to the comparator's power pins. A square wave of 1 kHz is applied to one of the inputs of the comparator. The output of the comparator should ...
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1answer
157 views

Where does the 1V voltage come from?

I have a four PLC with many digital I/O connected similarly to the schematic below. If I use multi meter and measure the voltage between the two points in the schematic, why is it showing 1V? Isn't it ...
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1answer
70 views

Do I need a common ground wire for differential voltage measurement?

I'm using this module as a digital scope and function generator. I don't have experience with differential measurements(besides multimeters) and I'm wondering do I need to couple a ground wire between ...
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59 views

Multiple readings on voltmeter

I have a DC voltmeter ammeter display that I want to use for reading voltages (up to 30V) on different channels in a power supply. That display is to be integrated in the supply so I can't do it ...
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4answers
72 views

High Voltage (0-600V) DC Voltage Sensing, Shared Ground with Isolated Converter and HV-

I'm designing a circuit to detect when the voltage across two DC input lines (HV+ and HV-) is greater than 60V. The voltage will vary from 0-600V. A seperate supply of 12v and 5v is available for use. ...
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1answer
52 views

Non linear DC voltage conditioning

I do not want to use any adc or dac. I want to see if this is possible by pure analog circuit. Any google links or book names are welcome. From 0 to 1000mV output should be 0 to 100mV. Then from ...
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1answer
67 views

How to set the resistor value for INA219

I managed to understand how to write/read data from the INA219 directly, using just linux/i2c-dev. When I was planning my PCB and Bill of materials with my supervisor he suggested I should use a 0....
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1answer
100 views

Measuring mains voltage with DMM and only one probe gives 100+ volts!

While trying to find out what is going on here , when measuring the mains voltage with a multimeter by connecting the red probe to the line and leaving the black (com) one laying in the floor after ...
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3answers
134 views

Detecting very low voltage audio signal

[Note: the initial text of this thread was edited] I'm trying to do the simpliest circuit possible for muting tpa class-D amp boards (tpa3118, 3116, and so) in the absence of input sound/music - yeah,...
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2answers
45 views

LED voltage indicator - why don't these LEDs blow?

I want to make a simple voltage indicator for my 75VDC power supply. I was thinking one LED for ~12V, one for ~40V, and one for 70+V. I found this simple instructable online, which, for 3V-30V, ...
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2answers
71 views

How do I take proper voltage measurements on device with multiple voltage sources sharing the same ground?

If you recognize me, it's in reference to CRT scopes again. I don't understand how to take proper voltage readings on the circuits. An example is the heating element in the CRT. When I hook both test ...
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1answer
40 views

Error Analysis due to Voltmeter Constraints

I got a situation: at the moment I am unable to access both channels for Keithley 2182A nanovoltmeter using LabVIEW. However, for some odd reason, while I cannot access the channels at once, LabVIEW ...
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1answer
34 views

(YHDC TV19) Circuit Diagram

Hi I want to use my (YHDC TV19) voltage transformer to measure 230 V ac supply using ADC, please help me with the value of current limiting resistor and burden resistor. (provide me complete schematic)...
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26 views

Understanding IMON and PMON in LT2940

I have two 12 bit ADC-channels that I am suppose to use in order to read measurement pins in lt2940: Imon Pmon To make it easy, I have 16 Vin and want to scale the input so that I can calculate the ...
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1answer
49 views

How to measure a signal generator with an oscilloscope probe?

I have a signal generator and an oscilloscope. When I connect a plain BNC cable between them, and I generate a square wave, I see the square wave on the oscilloscope with the correct voltage. ...
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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?
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1answer
22 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 ...
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1answer
56 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 ...
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3answers
93 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 ...
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1answer
33 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 ...
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28 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) ...
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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 ...
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2answers
93 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 ...
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2answers
154 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
65 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 ...
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0answers
105 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 ...
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1answer
100 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 ...
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1answer
71 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 ...
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3answers
69 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 ...
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0answers
108 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....
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0answers
59 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 ...
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2answers
89 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 ...
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1answer
77 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 ...
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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 ...
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1answer
42 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 ...
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0answers
37 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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