Questions tagged [voltage-measurement]
Act of measuring voltage
582
questions
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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, ...
0
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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 > ...
0
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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 ...
0
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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
...
1
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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 ...
1
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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 ...
1
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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 ...
0
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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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0answers
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. ...
1
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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 ...
2
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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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0answers
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 ...
0
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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.
...
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?
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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 ...
0
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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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0answers
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 ...
0
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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 ...
3
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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 ...
1
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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 ...
1
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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 ...
0
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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 ...
2
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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....
1
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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 ...
3
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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 ...
0
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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 ...
3
votes
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
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 ...
0
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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 ...
