Questions tagged [voltage-measurement]

Act of measuring voltage

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Measuring 12V car battery voltage precisely from the output of an ideal diode controller

I'm designing a device that will be plugged into the OBD2-port. One of the features is reading the battery voltage on demand directly from the diagnostics port. In order to protect the device from a ...
AlectronicZ's user avatar
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2 answers
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Comparator as a current detector with shunt resistor v2

I have a comparator with a shunt resistor that measures the voltage and when the voltage of 12 V from the source exceeds the Vref (1 V in my case) it switches to "high" output. I would like ...
Tomcat55's user avatar
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Comparator as a current detector with shunt resistor

I would like to design in OrCAD a comparator with a shunt resistor that will measure the voltage and when the voltage value is exceeded it will flip. I have designed the comparator but I don't know ...
Tomcat55's user avatar
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Peak voltmeter detector explanation

I'm designing a peak sinusoidal and impulse detector, based on the old design of a peak voltmeter designed by Haefely. I have the schematic, but I can't understand how this circuit works. The large ...
juliancaba's user avatar
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I have low voltage circuit isolated from high voltage through using PC817 optocoupler and how do I measure the voltage for high voltage circuit

I need to measure the voltage of output supply which is of 24 V. I have used a voltage sensor for this but for this sensor I have to connect input supply which makes isolation redundant
Yukta Sanghvi's user avatar
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1 answer
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Transformer ratio changes when varying voltage on primary

I want to measure mains voltage using a transformer. bought a 9V transformer, removed the secondary and rewind it with 10 turns that gives me 2mV per volt 1:500. The problem is that the ratio is not ...
ElectronSurf's user avatar
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When I attempt to measure Vbc for the circuit below, the LED partially illuminates when the switch is open. Can someone explain why please?

When I measure Vb relative to ground I get a value of 0.00V and with Vc relative to ground I get a value of 7.15V when the circuit is open. Subtracting Vc from Vb I obtain -7.15V for Vbc which is ...
J R's user avatar
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Circuit for Reading Power Supply Voltage with Micro ADC

I am working on a project where I need a microcontroller ADC (3.3V range) to detect the voltage being put out by a 24V variable power supply. This is the circuit I came up with to accomplish this: ...
Emmett Palaima's user avatar
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1 answer
71 views

Troubleshooting an Electrical Circuit - Is This an Expected Voltage Drop?

I am troubleshooting an electrical problem and am having trouble understanding the readings I am seeing on my digital multimeter. I am a DIYer with just the basics of electrical engineering knowledge,...
lp1756's user avatar
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How do I measure the noise at the top of a square wave?

I am trying to get a good measurement of the "quality" of a square wave, both in its flatness and lack of noise at both high and low levels. Low level is easy, just use a preamp and zoom way ...
rspaudio's user avatar
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Monitoring external battery voltage with ESP32

I'm trying to monitor a battery that is unrelated to my ESP32. The battery powers my gate and the ESP32 is powered by POE. The battery is a 12v battery. I am using a voltage divider and the ADC to ...
Paul B's user avatar
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How do I best protect a PLC and power supplies from voltage and current spikes coming from actuated components?

Problem My PLC is getting voltage spikes in the onboard ADC readings when I turn on actuated components elsewhere in my electrical system. I need to protect my PLC from these spikes because they ...
Jman's user avatar
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How to properly measure the power being delivered to a BLDC?

There's a battery connected to an ESC, connected to the Motor, coupled to a Dyno. How can I measure the electrical power going into the BLDC? As far as I'm concerned a simple measurement of line ...
Je parle avec toi's user avatar
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1 answer
28 views

Measuring voltage but no power with DMM

Hello guys i am a novice electronic engineer and i run up to a question on some troubleshooting i was doing. I have an old audio door phone system that has 2 designed outputs for the 12VAC electric ...
j_pentester's user avatar
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139 views

UC3842 IC not working

I have a simple UC3842 IC and I want to test that. First I used the open loop circuit from the datasheet but it didn't work therefore I went through the datasheet again and found from the schematic ...
kam1212's user avatar
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Can I measure pinholes in a dielectric layer using LCR meter?

I have a thin dielectric film (~1 um) and I want to measure the quality of the film in terms of not allowing leakage current through pinholes. Can I use an LCR meter for this purpose? If yes, how? If ...
SNIreaPER's user avatar
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How to measure the electrical properties to ensure the performance of a thin electrode/insulator stack-up?

I am a mechanical engineer by trade, and I am looking at some basic electrical properties that I need to measure to ensure the device meets the desired performance. The device consists of a two-layer ...
SNIreaPER's user avatar
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2 answers
145 views

Why would my true RMS multimeter give me a different AC voltage reading than my scope at frequencies above 2 kHz?

Here’s the circuit and my problem. My function generator is simply parallel connected to a multimeter and my scope. No load is connected and I am not using a scope probe, just a BNC connector with ...
Mike Meschi's user avatar
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Pipe to Soil Potential Measurement

I want to measure pipe to soil potential using a microcontroller. Generally, the potential difference between pipe to soil is negative. I found this circuit online. Is this circuit correct for ...
Mehedi's user avatar
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Questions about connecting ADS1115 for voltage measurement

Purpose: to measure the voltage on the DC bus (about 600VDC). ADS1115 Datasheet I looked at the use cases and saw two connection options (in the first case, we use two inputs, in the second, only one)....
Delta's user avatar
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Why 230 V shows up in a staircase light circuit even though 'live' is disconnected? Why is there no continuity between the light bulb and neutral?

There's a staircase light circuit in my house similar to the one shown below. I disconnected 'live' from the switch on the left and measured the voltage between its 'L1' terminal and neutral and then ...
Skyferix's user avatar
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1 answer
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Sigma-delta modulator (ADC), can it be used without sinc3 filter?

Purpose: isolated measurement of DC voltage (about 600V). For these purposes, I found two options: ADS1115 (I2C ADC) + I2C digital isolator CA-IS1204 Isolated Sigma-Delta modulator I am considering ...
Delta's user avatar
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3 votes
4 answers
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Can I use capacitor to measure time?

I want to measure distance by electromagnetic wave travel time. Capacitor charging voltage on time dependency is well-known: \$V_{capacitor} = V_{source}(1-e^{\dfrac{-t}{RC}}) \$ Equation above is ...
Stdugnd4ikbd's user avatar
1 vote
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What is the best setup for low frequency AC simulation and recording?

I need to apply an AC signal (current) of frequency, 0.1 Hz to a device and record the resulting change in voltage over time. I've been thinking a for a long time the best way to achieve this. I have ...
Simon's user avatar
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2 votes
3 answers
626 views

Op-amp subtractor circuit

While using Op-amp as a subtractor circuit the input applied to inverting and noninverting terminals are generally referenced to the DC ground of the circuit as shown in the picture below. Pic credit:...
Satya's user avatar
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3 votes
1 answer
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Help on creating a Li-ion battery cutoff circuit

I am trying to make a PCB for a drone run off of Li-ion batteries for a project of mine. I wanted to protect the drone and cells from an Undervoltage situation and cut off the Li-ion battery from the ...
Texas-72's user avatar
2 votes
2 answers
52 views

I want to make use of an Allegro A1324LUA-T Hall sensor to sense a very small magnetic field change. Would it be possible?

I am looking into using an Allegro A1324LUA-T for sensing very small magnetic field changes. The data sheet shows that the sensor gives a 5mV/G change in voltage so I can sense a 0.1 Gauss change if I ...
assasinchop7's user avatar
3 votes
2 answers
176 views

Small circuit explanation

I apologize that this is really simple for specialists, but since I am not one, I would like some assistance in this regard. What is the electrical condition of the resistors, please? They operate ...
Farz's user avatar
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Back to back P-MOSFETS for power sources OR-ing

I am trying out a circuit that is supposed to allow for two power sources. It is based on the one at https://electronics.stackexchange.com/a/549083/35737 simulate this circuit – Schematic ...
kellogs's user avatar
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Checking voltage of battery with a USB connector

I soldered two wires on female USB type A pins,one wire to ground and the other to the VCC pin. I was trying to check the battery voltage of the li-ion battery in my flashlight, I connected the a ...
xchcui's user avatar
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4 answers
66 views

Can you measure a powerbank's battery voltage at USB input connector?

I'm currently building a portable device, that is powered by a powerbank. I want to be able to measure the current battery "percentage" of the powerbank, with an esp32. For this i thought ...
Tom4211's user avatar
1 vote
1 answer
100 views

Voltage divider circuit for DC voltage measurement with protection against AC voltage?

Need some help with making a simple voltage divider to sense DC voltage of 0-30 V range with my DAQ which accepts 0-10 V analog input. I was wondering if the input voltage is by mistake an AC voltage, ...
Shamooooot's user avatar
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0 answers
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How to fix this error on DAC0808 with LF351?

I am testing this schematic from the DAC0808 datasheet at 10kHz frequency digital input, current 0, 1 and 2 mA but output had error see fig.Vout should slightly than this. How can I decrease this ...
Phongpit Sribua's user avatar
3 votes
1 answer
473 views

How to solder stainless steel electrode to PCB pad?

My goal is to solder stainless steel electrodes to a PCB in order to make a device that can measure differential voltage measurements from a surface. How do I attach stainless steel to a PCB to create ...
dinoswords's user avatar
1 vote
3 answers
140 views

How to remove 5V from circuit so that my meter reads correctly after LiFePO4 upgrade on golf cart?

A while ago, I upgraded my lead acid batteries to LiFePO4 for my golf cart. The state of charge ("SOC"/battery gauge/voltmeter) is for a 48V cart but the new batteries put out 53.x volts so ...
DIYCrazyMan's user avatar
1 vote
6 answers
232 views

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 ...
Dominik Koepf's user avatar
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1 answer
75 views

Adjusting signal voltage range for ADC [closed]

Can anyone please help me design a system using an LM324 op-amp to amplify a small voltage signal (from -20 mV to 31.1 mV) to a larger voltage range (0 to 5 V) so that it can be read by an Arduino's ...
SANJAYA LAKAJU's user avatar
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1 answer
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DMM showing voltage when one lead is hanging in air

My meter gives me a reading when I connect the positive lead to something and the com lead is just hanging there. Is this the voltage difference between the air and what ever my positive lead is ...
Ethan Richards's user avatar
5 votes
3 answers
307 views

What is the maximum Vref allowed on LM431?

I was looking at the answer given by Jasen Слава Україні in this thread High Voltage (0-600V) DC Voltage Sensing, Shared Ground with Isolated Converter and HV- The author needs to detect a voltage ...
Tom Ben Dan's user avatar
1 vote
4 answers
526 views

Isolated DC voltage measurement via optocoupler

I am trying to make a circuit that measures 10-30V DC with isolation. The measurement is done by the circuit, not manual. The measured voltage level/information is sent via an optocoupler to the ADC ...
elec3's user avatar
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0 votes
1 answer
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Turn on LED when input is in range only

I have a car HVAC daughter board that set a pin to a specific voltage depending on which of the 6 physical buttons is pushed. I don't have any schematics neither datasheet. I measured voltage of this ...
Balobiana's user avatar
1 vote
1 answer
122 views

How to design an accurate (1 μV error) meter

I want to design an accurate LV meter. The range is from 2.5mV to 50mV both AC, with a 5uV accuracy. This comes from a shunt resistor that is connected to AC main (230V AC). Hence it will go below 0V. ...
JoeyB's user avatar
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Help Testing ATX PSU 8 Pin PCIE Connector

I'm trying to do some pin swapping on an 8 pin PCIE power cable. It didn't come with my PSU, so I know it's probably not going to work how it is. I've done research on how to test and swap the pins ...
Austin Strand's user avatar
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0 answers
72 views

Voltage control tri-phase current circuit at 10 kHz frequency

This is my circuit that use to control tri-phase current (tri-phase is positive, zero and negative). This circuit include two voltage control current by first will release positive current at the top ...
Phongpit Sribua's user avatar
-1 votes
1 answer
78 views

How do I find out if a product can work on 240 V? [closed]

How do I check if a product can work on 240VAC? For the impending winter, I bought a desk heating mat from an online seller in Australia (where mains electricity runs on 220-240VAC). I received an ...
happybuddha's user avatar
3 votes
2 answers
210 views

Read battery voltage with ADS1110

I have an ADS1110 that should read a battery's voltage (2.8V - 4.2V). I have built this schematic: The problem is, I connected the battery's negative terminal to VIN- and the PCB is already assembled ...
Cem Pamir Bana's user avatar
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0 answers
41 views

Measuring voltage across one end of a 50 ohm bias T and the other end is 50 ohm terminated

I was looking to measure the output voltage from one of the PCBs using a multimeter. I connected the center of the 50 ohm T adapter to the DMM, one end of the T adapter to the output port of the DUT i....
devd's user avatar
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3 votes
1 answer
100 views

Simulating HCPL-3700 using LTSpice

I am trying to simulate HCPL-3700 using the LTSpice model provided by Broadcom. Following the application note 1004 example 1, I am able to successfully calculate the Rx value and simulate the model ...
raj's user avatar
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1 vote
1 answer
39 views

How to measure a specific part of a voltage range using a microprocessor like an Arduino

I wish to monitor a battery using an Arduino. I can successfully measure the value using an Arduino via its Analog port, which gives me a 1024 bit value range. Where I'm stuck is how to allocate that ...
Markus's user avatar
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2 votes
1 answer
232 views

Why is my 3-phase power giving me two 180 V phases and a 40 V phase?

I have 3-phase power hooked up to my building. I also have solar panels feeding the grid. Most of the power in the building is functioning normally. I tested the phases with a multimeter and got 120 - ...
IssacharWEB's user avatar

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