Questions tagged [voltage-measurement]
Act of measuring voltage
-2
votes
2answers
65 views
Protecting against over voltage but with minimum leakage current
I have a circuit where I sense an input which is a voltage divider with resistor.
Since the voltage divider needs to have high impedance, the current flowing through is in the range of 10's of uA.
I ...
0
votes
5answers
97 views
What kind of tool is used to record a voltage over time to a PC file like a waveform?
I don't have any training but am doing some hobby electronics. I would like to record a change in voltage over time, sampled at around 100+ kHz. Ideally, I'd like to record around 20-30 min of two ...
-5
votes
1answer
80 views
Autoranging Ohmmeter [on hold]
Note: before i explain my issue i would like to note that I am a beginner in electronics please pay attention to that when providing solutions and explanations. Thank you.
I have succeeded at making ...
1
vote
2answers
32 views
Measuring floating gate potential with minimal leakage current
I am working on a sensing device where the voltage of a floating node is dependent on the quantity to be sensed, as well as the net charge stored in the node. I would like the device to be only ...
0
votes
1answer
24 views
Can I add an INA219 voltage\current sensor to this USB powerbank?
I have a Raspberry Pi Zero in a small robot that I have been powering off a USB powerbank and it works great. Unfortunately when the USB battery goes flat the power is cut and the Pi crashes. I want ...
6
votes
4answers
1k views
Measuring AC voltage without a transformer using a microcontroller
As I have no practice with AC voltages, I'm asking if the following circuit is reliable for measuring AC voltages about 110Vca and 220Vca 50Hz/60Hz.
I have already made it with a small transformer. ...
1
vote
1answer
45 views
Measuring input voltage with 3.3V ADC MCU
I am designing my very first DC motor driver circuit. Right at the start, I want to be able to measure the input voltage to the system. The system supposed to work with external DC power supply from ...
1
vote
1answer
33 views
Is it appropriate to use a 300V RMS CAT I rated oscilloscope to measure 230V RMS of a power inverter?
Yesterday I decided to look at the waveform of my portable power inverter. The inverter specs are the following:
Input: 12 V DC
Output: 230 V RMS
Rated power: 300 W
I powered my inverter from a ...
2
votes
4answers
45 views
Measuring SuperCap current leakage avoiding voltages drops in ADC
I have a circuit with a SuperCap used as a battery. I want to know the curve of SC voltage in time to finnaly measure its self-discharge.
Is this can be done with a simple arduino or another ...
0
votes
1answer
85 views
How to determine DC input voltage of a device without its charger? [closed]
Had a MotoMaster (Canadian Tire) 27/3 LED flashlight for 4 years now. Model was discontinued 2-3 years ago. Lost the charger at least 2 years ago and the light's battery FINALLY died today (!!)
I ...
0
votes
1answer
83 views
INA219 measure voltage of battery with RPi
simulate this circuit – Schematic created using CircuitLab
I want to measure voltage of 12V battery powering something by INA219 connected parallel to this battery and read it with RPi via I2C. ...
0
votes
1answer
55 views
Is there some way to measure mains voltage with the ACS712 sensor?
Last year I went to a maker event where some guys used an ACS712 sensor with an Arduino to monitor the mains voltage and current to monitor the energy cost in the house.
One thing I saw there is that ...
1
vote
2answers
157 views
Why do I measure (almost) no voltage between 230V phase and my body?
The other day I was experimenting with a multimeter and checked the voltage in one of the electric plug at home. Without surprise I measured around 230V between phase and neutral and also 230V between ...
0
votes
0answers
43 views
Advantages and disadvantages of voltage output vs. current output PMT modules
Context: I am building a custom right-angle static light scattering setup to measure aggregation of biomolecules in aqueous solution. I need the instrument to be as sensitive as possible, to allow ...
0
votes
2answers
87 views
How come no voltage is meassured across my electrolysis tank?
I've built myself a electrolysis tank, using a plastic barrel as the container, rebar as the sacrificial cathode, a 12v 15A car charger (DC), and a Sodium Carbonate solutions as the eletrolyte. The ...
1
vote
1answer
87 views
Measuring 200 volts safely
While I can measure line voltage safely, I need to write a procedure to have someone else measure the voltage. The load is pure resistive,and I want to measure the voltage across it, with a battery ...
1
vote
0answers
36 views
Trouble with biased measurement for Oxygen Sensor EC410
I need to achieve a -600mV bias between Vsense and Vref for a potentiostat circuit.
I'm trying to replicate the design for an Oxygen Sensor (EC410) by following the above image from the application ...
2
votes
2answers
84 views
Ground loop via pull-down resistor
I'm developing an STM32-based device, one of whose functions is to periodically monitor the main power 12V battery voltage.
I created a simple switching circuit with a voltage divider. I have added a ...
0
votes
0answers
31 views
Measuring small strain with strain gauge, how nullify errors?
I have a similar circuit like
https://www.egr.msu.edu/classes/ece480/capstone/spring15/group05/uploads/4/7/5/1/47515639/ece_480_app_note_justin_bauer.pdf
2. page bottom
Wheatstone bridge:
2x 350 ohm ...
0
votes
1answer
40 views
in-amp for strain gauge
I'm working on a project where I should send an overload signal if the strain is bigger than 40 ppm.
So far I found this answer:
Strategy to balance a Wheatstone bridge for strain measurement
The ...
0
votes
1answer
42 views
Can one voltage output from OpAmp read with two ADC inputs?
this might be a little silly question, but please advise me. I am trying to use two photodiodes (one for the absorbance measurement and one for the source of the light as a reference) and the voltage ...
0
votes
0answers
19 views
Topological observibility in OPP problem
I have a short question about observability analyzing constraint in optimal PMU placement problem in power system. Observability analyzing has two method: numerical and topological. Most of papers use ...
0
votes
0answers
47 views
Rectified X2 circuit gives 2 voltages depending on how the powerplug is connected to the wall (EU)
simulate this circuit – Schematic created using CircuitLab
I'm trying to control a mosfet directly from a phase shifted 50Hz sine wave. But when I was trying to understand the voltage drop with ...
0
votes
0answers
24 views
LTspice modelling for the end terminal side
So I have this model. I am trying to build a current/voltage converter circuit for a bus carrying current to the other end of the bus, because I need to give this voltage output from the amplifier to ...
0
votes
0answers
67 views
Step up transformer protection
simulate this circuit – Schematic created using CircuitLab
Hello, i have question regarding the short circuit current at both primary and secondary side of the XFMR2.
Given the values in the ...
1
vote
2answers
68 views
Measuring crystal drive strength without a current probe
TL;DR
Is there a means of measuring the crystal drive level reliably using voltage measurements (even with a differential voltage probe)?
Background:
I am attempting to measure the crystal drive ...
0
votes
0answers
91 views
Non contact voltage tester
I built myself a very simple non contact voltage tester with a couple of transistors, an LED and a wire at the end to work as an "antena" like the picture demonstrates:
It's for a school project and ...
0
votes
2answers
261 views
How to measure output voltage and current of a VFD?
Is it possible to measure the output of a Variable Frequency Drive without relying on it's display data? I tried to measure the line voltage with a DMM and current with a clamp meter but it shows ...
0
votes
1answer
49 views
circuit for mesure positive & negative voltage + Vref resolution
i would like to make a "voltmeter" to read from +2V to -2V and connect it to an Arduino ADC ( 0V to 5V ).
I found different configurations for do this job:
From this site:
Bipolar to unipolar ...
1
vote
1answer
105 views
Can I use a twisted pair for 5V and ground?
I'm going to use a RS485 modbus connection which requires a twisted pair. Now I also need power, that will be a 5V line and a ground. The distance will be about 3 meters max. Can i use a twisted pair ...
0
votes
1answer
32 views
Avoiding accidental earthing, voltage rejection, and voltage dividers for a motor control output circuit
I'm trying to connect up an integrated control DC motor with a 24V output (Motor manual - relevant page p32) with my 10V PLC (PLC Manual), and looking for a little help please.
I don't understand why ...
-1
votes
1answer
46 views
Whats the equation to calculate the Vo-w and Vp amplitude of this Wien Bridge oscillator?
Im trying to find the equation to the amplitude of this wien bridge, if you could help me that would be awesome
0
votes
1answer
66 views
Problem with mesuring value from current sensig pin on VNH2SP30
I connected the Monster Motor Shield (based on the VNH2SP30) to the Arduino Uno and successfully drive the engine, but I can not measure the value from the CS pin on this board (the voltage at this ...
2
votes
0answers
56 views
Is a 90V output spike normal for a 45V buck boost converter?
The LT5176 buck boost converter outputs a short 90-91 volt spike at at the output in the 2nd second after startup, applying power to Vin.
Schematic
More details at Why does this buck boost with ...
1
vote
1answer
34 views
Isolation of voltmeter via DC->AC->DC conversion
I bought a combination ammeter/voltmeter which has the restriction that the measurement/display circuitry must be powered from a different source than the measured voltage.
What is the underlying ...
0
votes
0answers
43 views
Sensor that identifies the number of objects in a stack of casino chips
I am not a technical person so please bare with me and don't laugh of my technical descriptions or wording.
I'm working on a new invention that requires a sensor to identify the number and position of ...
0
votes
0answers
51 views
Interfacing external high speed ADC techniques
I am designing a power converter for solar micro-inverter based on fly-back topology (step-up).
I have to extract maximum power from the solar panel and for this I analyze voltage and current change ...
1
vote
0answers
47 views
Precision battery voltage meter, Auto adjustment by R-2R
For a more precise measurement of a battery voltage I'd like to apply auto adjustment. The input voltage ranges from 2.5V-4.2V (single cell) to 20V-72V (module). At the moment the input voltage is ...
0
votes
0answers
67 views
Resistor Discoloration
I am working with an existing design and seeing a 200Ω, 2W resistor becoming discolored in the field (customer questioned its condition), but not appearing to fail. I measure resistance and is 203Ω, ...
0
votes
2answers
275 views
Voltage divider to measure 12v battery with arduino low consumption
I want to measure 12v. Car battery with arduino. Three questions:
Is the R1 and R2 the best values? The car battery can go from +10v. To +15v.
How and what can I use to save power between the ...
2
votes
2answers
69 views
Measure High Dc Voltages 0-150V using a STM32F446RE MCU
Does anyone have any suggestion on how to build a circuit that can convert high Dc voltages from 0-150 V to lower voltages so that I can use my MCU to read them and display them on my 16x2 LCD?.
I ...
2
votes
1answer
311 views
How To Detect If Two Voltages Are The Same And Trigger An Output If They Are
Basically, I'm struggling to design a circuit with the following requirements:
Requirement 1: Output is high (say 5v) when the two input voltages are different. [If it makes it any easier the output ...
1
vote
5answers
219 views
Use LEDs to indicate voltage
I want to design a circuit that has 3 LEDs connected to it.
When the voltage of the power source connected to the circuit is...
3.6 volts I want only the first LED to light.
7.2 volts I want the ...
0
votes
3answers
125 views
Is a fuse the right way to measure current
I saw my friend in a workshop use fuses to measure current of a generator and he said that a fuse is more accurate than connecting a light bulb because the light bulb works in current range.
My ...
0
votes
1answer
38 views
How is the voltage across a capacitor measured in a passive LPF circuit with no ground?
Say we have a low pass filter circuit as the one that follows:
If I want to study how the charging/discharging of the capacitor works, I need to apply the universal equation for voltage. However, ...
0
votes
1answer
31 views
Max allowed measurements error
Since it's not possible to know with 100% accuracy about what's going on in a circuit and its components, and I have to trust my multimeter on measurements, what's the usual approach to managing ...
1
vote
2answers
137 views
Is it possible to measure the voltage and current of a load with this circuit and Arduino?
I'm trying to measure the voltage and current for a DC-AC converter in my car with Arduino.
I know it would be easier, more accurate and cheaper to use breakouts with INA226 like this. But this ...
0
votes
1answer
62 views
Measuring the minimum voltage square wave
I would like to measure if an 1 kHz square wave signal ±12V 10-80% duty-cycle has a minimum voltage of -11V at Vm.
simulate this circuit – Schematic created using CircuitLab
So I would like to ...
0
votes
2answers
55 views
Automated voltage measurement: Tradeoff between PLC and averages
I am setting up an automated voltage measurement of a precision device. In my case, I am using a Keithley 2000 and controlling it over RS232 from MATLAB.
The voltages I am measuring have to be quite ...
2
votes
3answers
140 views
Anomalies while using transistor as switch
I have started learning Transistors from this Tutorial by Sparkfun - https://learn.sparkfun.com/tutorials/transistors . I understood that while using Transistor as a switch it operates in Cutoff or ...
