# Questions tagged [measurement]

Measurement is the assignment of numbers to objects or events. All measurements consist of three parts: magnitude, dimensions (units) and uncertainty.

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### What are the disadvantages of crocodile (alligator) probes? [closed]

When measuring with an oscilloscope, I use an original high frequency oscilloscope probe and a double side crocodile (alligator) clip and the results are usually very close. Note: it is called ...
5k views

### How do you measure a distance along the Z axis in Altium?

If you hit CTRL+M, it's easy to take a measurement along the x or y axis. If you want to measure along the Z axis (for instance, the height of a 3D body), how do you do it? I googled "measure the ...
78 views

### Imperial measurements [closed]

I am studying electricity, electronics, and electrical engineering. Could somehow show me how to use the below pictures, which cover conversions? I know it is showing conversions for metric and ...
120 views

### How to measure multiple resistances with Arduino Uno, without one measurement influencing the other?

I'm working on a project where I aim to measure resistances using an Arduino Uno. I started with two separate voltage dividers, each using a 1 MOhm reference resistor, connected to a common Arduino ...
1 vote
151 views

### Pressure sensor for breathing

Could anyone suggest the type of pressure sensor I need to measure human breath? When someone blows into the device I want to measure them blowing in and also sucking out. Could this be done with ...
89 views

### How to measure Lithium-ion battery SoC?

I have a 48 V 12 Ah Lithium-ion battery pack. I am struggling in finding a way to measure its State of Charge. It will be charged through a 13S JBD BMS. I need to spit out information from the battery ...
1 vote
325 views

### HLW8032 energy meter circuit showing power usage at no load

I am designing an AC energy metering circuit. The circuit has to measure voltage, current, power, power factor and energy used for two channels (from the same source). The HLW8032 transmits 24 bytes ...
143 views

### How to calculate frequency of an AC source with variable frequency using Arduino

I have an AC current source. Its properties are Maximum Vrms=15v Maximum Frequency 125 Hz Minimum Frequency 5 Hz The current source is pickup coil of a motorcycle... Vrms range is approximately 0.7v-...
51 views

### How to Read Unipolar Square Waves on TRMS Multimeter

I'm trying to switch from reading my high-voltage unipolar square wave signal from a benchtop oscilloscope to a handheld multimeter, but I don't understand why my multimeter is giving the voltages it'...
166 views

### differential measurement vs ground

I am looking to measure an incoming V vs ground with an ADC (MCP3424 or equal). The Vin vs Gnd can be anywhere from -1.5V to +2.0VDC. I looked at using an op amp with level shift, when I came across ...
170 views

### Does this inductance measuring oscillator circuit work?

I'm planning to create a circuit to measure inductance by creating a stable sinusoidal oscillator out of it with a known value capacitor. Then measuring the oscillator frequency accurately with an ...
769 views

### Using 50 Ω coax cable instead of passive probe

Preface, why am I asking this question? Instead of using a passive probe with a ground clip, I want a more "permanent" and reliable connection for my measurements. Note: I'm not talking ...
6k views

### Oscilloscope: when to use coaxial instead of probes?

I understand the difference between passive and active probes, and between x1, x10, x100, ... I also understand that at high frequencies the capacitance of the oscilloscope has to be considered, so a ...
166 views

### Which equipment is required to test the no radio device for compliance with electromagnetic compatibility (EMC)?

I am designing a device that has no intention to transmit or receive any radio waves but it has CPU, large PWM driven LED indicators so may be some higher frequencies inside. To make sure we pass the ...
66 views

### What is the real resolution of my voltage measurement when I use only some of the range of of the ADCchannel

I have a 16 bit ADC, I use the +/1 V range, differential channel. If I used the full range of the ADC to provide full resolution (I am aware non-linearity and noise may affect this) this calculates as:...
1 vote
197 views

### Measurement of output current of a photodiode

I am a German student. My task is to conduct a characterization of a photodiode (KPEIMC-UDCOM by Kyosemi.) The photodiode will be illuminated by 850-1550 nm laser diodes. It would be good (but not ...
1 vote
3k views

### How to calculate measurement error in a voltage divider?

I'm trying to calculate the measurement uncertainty of the voltage represented by the ADC in +/- V or % of a voltage measured across R2 of a voltage divider. What would be the general way to tackle ...
107 views

### My isolation transformer has its protective earth connected to the output neutral. How should I rewire it for my home lab for "DUT probing"?

I have a rather sturdy isolation transformer in my home lab and I just realized that the primary side earth is not only connected to the output side earth but also to the output side neutral. I don't ...
51 views

### What does an accuracy of 0.1% + 20 mV mean in a power analyzer's data sheet?

I need to know the measurement accuracy of Keysight N6705C power analyzer. I came across this document (N6700 Modular Power System Family.pdf) that states the error in terms of a percentage plus a ...
30 views

### Understanding Voltage Read in Voltage Divider for NXP S32K118 Microcontroller ADC

I am having a bit of a hard time understanding the voltage read in the voltage divider that is being an input for an ADC to an NXP microcontroller, S32K118. Below is the schematic of the circuit. ...
1 vote
189 views

### dB SPL Calculation is not making sense- values are seemingly too high

I am using an electret with a sensitivity of -38.44 dBV to make sound measurements at a distance of 1m. I decided to add an amplification circuit with a gain of 125. So in the end to convert to SPL, I ...
1 vote
185 views

### Number of data points needed for INL DNL estimation

In this article where ADC of pico pi is characterized, I found a part that I have never encountered in my study of mixed signals design: I don't understand how we number of data points needed is ...
172 views

### Uncertainty of output current in voltage-current converter

I have a problem comprehending some things about uncertainty in electrical measurements. Here is illustrative example from my textbook. We use voltage-current converter for measurement. simulate this ...
22 views

### Determining Suitable TRMS Voltmeter Specs for Modulated Signal Measurement

I'm seeking advice on selecting a TRMS (True RMS) voltmeter suitable for measuring the voltage across a resistor with a modulated signal. Here's the scenario: I need to measure the TRMS voltage across ...
19k views

### What are the differences between a x1 and a x10 oscilloscope probe

I've heard pros of x10 oscilloscope probes a lot. Now I need to know the cons, but I couldn't find a clear explanation. Some people say x1 probe is for small signal. How do you decide either x10 or x1?...
268 views

### Is there a way to measure ripples in water with some kind of sensor?

Imagine you have a water tank on the top of a truck (like firefighters have.)Is there a way to measure how much the water ripples with some sensor? I know sensors that just tell you if there is water ...
206 views

### How does the FDC1004 (capacitance to digital converter) measure capacitance?

I am using the FDC1004 and wondering how it exactly measures capacitance. The datasheet is not explaining much. An associated application note contains a little more information, but still very little ...
1 vote
267 views

### Tektronix TDS3000 series max trigger rate

So I am making a testing stand for some equipment and I am using an old TDS3034C Tektronix scope for most of my measuring purposes. I've connected it to the computer via Ethernet and using PyVisa to ...
322 views

### LTC1966 Sallen-Key post-filtering application question

Just a quick question about an application circuit in the LTC1966 datasheet. Figure 13 on page 18 shows a third order (when considering output resistance of the LTC1966) Sallen-Key filter, with a ...
48 views

### Induction motors torque measurement

I am to calculate the running efficiency of a 3-Ph squirrel cage induction motor. I have the rated data for the motor. I have the load speed of the motor but I need output torque to calculate the ...
1k views

### VSD (Inverter) current measurement on 3 motor phases

I'm working on a project to build a rig for testing various sized Variable Frequency Drives (VSD's / inverters), the kind that you'd use to run a squirrel cage induction motor. The range would be from ...
864 views

### Measuring nA leakage current

I'm trying to measure some leakage currents of both a diode (expected around 5 nA) and a MOSFET (20 nA). My issue is my meter's measurement accuracy is only around 10 uA, and I need an accurate ...
15 views

### Pulse width modulation using ML4800CP

I am working on a SMPS (450 V output). It use an ML4800CP IC to control and manage 450 V DC. How can I measure the PWM signal using an oscilloscope? I attached it, and it worked well for the PFC ...
236 views

### Measuring integrated current

I want to measure the amount of light striking a photodiode in a specific time window (about 1ms). In this window, we get $10^6-10^7$ photons, which get converted into electrons with about 80% ...
85 views

### Why might my circuit's measured voltage drop when I add more load to it?

I have one of these power supplies: I also have an MCR-4V data logger: If I connect wires directly from the power supply to the data logger (red to red, black to black), then the voltage output on ...
204 views

### Mass paralled resistors for better tolerance [duplicate]

I hope this doesn't get people's eye rolling as a very rudimentary question... Here goes. I need a very, very precise resistor divider, say a 1/11 ratio. It doesn't really matter the ratio chosen. ...
1 vote
794 views

### Measurement of transformer with a vector network analyser (VNA)

I have a planar air core (no ferrite) transformer in a PCB. I need to characterize the transfer function of this transformer from DC to 500 MHz using a vector network analyser (VNA). My first ...
136 views

### Are LCR meters sensitive enough to measure PCB trace impedance? [closed]

How long is a piece of string? I’m working on an application currently where trace impedance appears to make all the difference on performance as observed on a few unguided experimental revisions of ...
937 views

### Series/parallel combination of resistance/capacitance in an RC circuit (wrt LCR meter readings)

I have this equivalent circuit I am working on. I have to find out individual values of all components in it. I can measure resistance, capacitance and impedance of the whole circuit. I am not sure ...
180 views

### Current drop with capacitor

I'm new to electronics, and there's something I can't figure out. Can someone explain to me why, when I add C1, the current drops drastically in R3? I was thinking that the impedance will be the same ...
657 views

### How "Zero" is this supposedly Zero-TCR resistor? And how much better is it than this other one?

I found a resistor at Digikey, and the TCR was quoted as being 0.0ppm/°C, and I had to check the datasheet just to refute my suspicion that it was a data entry error, and it looks real, but just how ...
2k views

### Reasons not to use these leads

I found the following note with a set of test leads we use for our Agilent 34461A[1][2]: This Test Lead Set is designed for use with the Agilent 34xxxA Multimeters, and also the U274A, U3401A, and ...
564 views

### Biased single-source relaxation oscillator not starting

Vcc is 5 V , first op-amp LM358 provides 2.5 V ground for easiest possible relaxation oscillator build with MCP661 (2.5/5.5 V supply, 60 MHz operational range). I wanted to use it to measure values of ...
140 views

### Can I measure the internal termination resistance of a MIPI receiver?

This question is further to: How accurate are internal terminators on chips with high speed differential inputs?. I would like to measure the actual termination resistance inside one of these chips (...
1 vote
100 views

### Measuring impedance on VNA

Question: I would like to measure the impedance and phase of an electric piezo tranducer with a resonant frequency of approximately 1MHz - a graph of impedance in Ohms as a function of frequency. ...
147 views

### Measure capacitance with Arduino and AD7746

I want to measure capacitance with an Arduino and an AD7746 capacitive sensor. I already used ChatGPT and some examples, but the sensor measures just 0 pF. When I measure with an LCR meter, the ...
1 vote
98 views

### Resistance measurement with DMMs

I had one doubt regarding resistance measurement from multimeters. I cannot show the schematic because it is confidential but I have added a circuit diagram. It refers to a gate driver circuit. I am ...
1 vote
37 views

### Comparison of two methods used to calculate capacitance

I need to compare two potential methods used to calculate capacitance, but I can't find the names for them to do some research. The first method: Placing a capacitor in a circuit with an 800 Hz ...