# 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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146 views

### How to estimate displacement error using accelerometer

I am using an MPU6050 and performing a double integration to obtain displacement, and this is to be placed in a vehicle that will be subject to about 2.5g. I cannot test it now, but how is it possible ...
30 views

### Low power rectification of AC component of modulated current signal

I have a current source consisting of a 100Hz sine plus a DC offset: $I=I_{DC}+I_{AC}\cdot\sin(2\cdot\pi\cdot 100Hz\cdot t)$ with $I_{DC}\approx100uA$ and $I_{AC}\approx 1uA$. I would like to ...
3k views

### How do you calculate the noise of an op-amp circuit?

I think I know how to do this, but you can find a lot of different instructions and calculators online that contradict each other. I have yet to find a clear, concise procedure for calculating the ...
229 views

### ICL7107 not working on breadboard?

I am building a very simple thermometer circuit on breadboard, based around the ICL7107. The 7-segment LED display I am using is made up of 3x TOD5261BE-N displays. My intention was to make ...
46 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 ...
93 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 ...
55 views

### Why footprint dimensions are to edges and not centers

Whenever I'm looking at electronic components, I regularly see footprints with this kind of thing: Dimension E seems to me to be somewhat unhelpful; rather than simply reading the centre distance (...
185 views

### Calculation of active power and apparent power through sampling

I'm currently working on a power meter device based on simultaneous sampling of current and voltage values, I intend to use this system to measure the active, reactive and apparent power on a non-...
94 views

### Finding Wilson Current Mirror Output impedance

I am trying to confirm my output resistance calculations with my simulation. How can I measure the output resistance seen by Q4 in order to confirm my calculations? How I measured $r_{o2}$ (image ...
1k views

### Ceramic capacitor value changes after soldering!

I am debugging a power amplifier circuit and trying several capacitors values to fine tune the design to meet the frequency response specifications. All the 0603 and 0805 ceramic capacitors are ...
50 views

### Get position along electric wire [closed]

Do you know the game called Buzzwire where the aim is to guide the grip mounted loop through the wire maze without touching the loop against the metal maze all the way to the end? is it possible to ...
217 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 ...
52 views

### Differential Probe measurement and Single Ended probe measurement (Using MATH function in scope)

I am measuring the differential voltage across a resistor connected between the supply (16.5V) and the ground. Below is my Circuit. Using differential probe (Probe setting 9.96:1), when I measure, I ...
62 views

### Measuring the activation time of a solenoid

I'm trying to measure the activation time of a pull-type solenoid. When the solenoid doesn't have a load connected to it, you can measure its activation time through the current it consumes. At first,...
66 views

### Test grounding of wall sockets

I just had (and solved thanks SE) a problem with a wall socket where the ground contacts were malfunctional. Much of the electrical safety relies on proper grounding. As far as I can read, details for ...
65 views

### How dual gyroscopes can be used to remove gyro drift?

I need to measure yaw/heading/azimuth correctly. Now, I have done with gyro with very strong filtering and the results are very low yaw drift and even when there is perfect calibration then there is ...
30 views

### How do I measure the fluctuation of a pulsed voltage of ~1700V?

The problem: See the little sketch. Starting from a high-precision DC power supply, I pass the voltage to low-pass filter and a pulser. This pulser pulses the nominal voltage of around ~1700V down to ...
350 views

### Determine to Assume Outer Diameter of Cable for Choosing Cable Gland

Is there any method to determine the cable outer diameter just only known from the pin connector which is M23 Connector 17 Pins? I need the method for choosing cable gland size. Thank You
99 views

### Period Measurement

I am reading a book about the measurement in communications. There are a lot of information about how to measure frequency and period of signals. OK, i have understood that we should measure the ...
37 views

### Requirements for measuring PCIe 2.5GT eye diagram

What is suitable equipment for measuring an eye diagram of PCIe differential pairs. I would like to evaluate the signal integrity of a PCI lane RX/TX/CLK 2.5GT. What is the recommended minimum ...
1k views

### Calculating AC Input Power

I'm making an AC to DC power supply that connects to mains. There's an AC to DC converter, buck converter and a smoothing LDO that outputs a DC controlled with pots. I'm verifying the supply, and ...
41 views

### Cortex-M DWT cycle counter inconsistent measurement

I recently discovered that it's possible to use a free running counter embedded in most Cortex-M4 cores to measure the performance of a chunk of code. I'm trying it on my LPC4370, where I want to ...
25 views

### measuring wireless (inductive) power supplies

I bought an electric toothbrush with a lithium-ion battery and wireless (inductive) charger. It came with one of those air/water jet flossing accessories, which also has a lithium-ion battery and a ...
102 views

### Measuring wow and flutter of a phonographic turntable with digital equipment

Old school way to measure: 3000 or 3150 Khz test tone from test record played back through phono cartridge/preamp into wow/flutter/drift meter and for turntable that has an electronic adjustment to ...
74 views

### Two different LED types: diode test on two different multimeters shows just “1”

I have two multimeters - granted, they're both the super cheap DT830B types, but slightly different models and one is straight from the packaging. I also have two bags of LEDs - bright red and bright ...
61 views

### Possible to measure output of each battery in a battery bank?

I've been working on a small project to add electrical to my utility trailer. I have two 12V 20Ah lead acid batteries wired in parallel for running a mix of lights, a winch, cameras, a ventilation ...
152 views

### How can I reduce an oscilloscope's bandwidth to that of an Arduino's ADC?

The typical sample rate of the Arduino Uno's ADC is ~10KSa/s. Yes it can be overclocked, but lets just consider the normal situation. I'd like to 'simulate' the levels of a large random signal that ...
272 views

### Is using a transformer at reduced voltage a bad idea?

My Google is failing me. I want to make an isolated AC voltmeter capable of working at 120 or 240 VAC. I've found a suitable 240 volt to 5 volt transformer to use (current capacity doesn't matter - ...
47 views

### To find theRMS noise voltage in a circuit, can the measured RMS voltage be subtracted from the RMS voltage of shorted probes?

I'm trying to estimate the SNR of a circuit, which includes measuring the noise power of an analog trace. Right now, I'm attempting to measure the noise with a high bandwidth scope probe, ac coupled, ...
129 views

### How does multimeter AC measurement work?

How does a digital multimeter measure AC voltage? My guess would be that the AC voltage is rectified and filtered into a DC voltage which is then measured, giving the peak voltage of the AC signal. Am ...
1k views

### Detect and measure fog outdoors

Currently working on a project requiring me to detect fog, and measure the amount of fog. It doesn't have to be accurate but it has to give a sense of how foggy it is. The device (probably Raspberry ...
26 views

### Custom Test Fixture for LCR meter

I've designed and built a custom test fixture (based on Keysight's 16047A) to be able to measure multiple pin capacitors. When testing it to compare both fixtures (the custom and the original), I ...
33 views

### Is there a way of measuring components in circuit? [duplicate]

I have some old circuit boards full of SMD components that I would like to reuse in my projects. Before going through the trouble of removing any from their old circuits, I would like to know if they ...
18 views

### Hspice derivative measure

Is it possible to measure value of input voltage at a point when derivative of output voltage with respect to input voltage equals some value? P.s. The analysis done is DC. The input voltage is the ...
22 views

### Derivation of resultant standard deviation from individual standard deviation of an expression

Consider a problem: The total current $I=I_1 + I_2$ in a circuit is measured as $I_1=(150 \pm 1 ) A, I_2=(150 \pm 2 ) A$ , where the limits of error are given as standard deviations , ...
51 views

Depending on the configuration, PLCs can often measure 0-10V, resistance or 0-20mA on the same set of screws. How to use the same screw terminal to measure resistance of an NTC element, voltages in ...
54 views

### How to measure VSWR of a single connector?

With a 2-port VNA, I would like to characterize the performance of a single coax connector, specifically to obtain VSWR. The specific situation is an SMA connector at the end of a short section of ...
38 views

### What is meant by the term “baseline noise” in this context?

I came across this article about oscilloscopes. Under the figures and scope screenshots there is a term called "baseline noise". I googled but it turned out this baseline noise is used at different ...
127 views

### How to measure S11 of antenna using VNA for one port S-parameter measurement?

I have an antenna. I want to measure S-parameters of it using a network analyzer. I am not clear how to do it. Please explain. Thank you
58 views

### How to use a pressure sensor (transducer)? [closed]

I have this pair of pressure sensors that are addressable transducers. I want to use them for a project but I don´t really get how to get them to work. I´m used to the type of sensor that has 3 cables(...
31 views

### How to route current for ATE?

I have many test points on a board, a small DAQ, and an SMU that I can program with LabView. Depending on the test, I need to change which test point the SMU is sending/measuring voltage or current. ...
39 views

### Contribution of solder parasitic to S parameter measurement

I have an antenna. I want to measure S-parameters of it using a network analyzer. The antenna has to be soldered to SMA cable for the measurement of S-parameters. After the calibration, will the ...
226 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 ...
121 views

### Probes gives different results

I discovered an "funny" thing today. I had used a GW instek probe GTP-150B-4 150Mhz in 10x mode and documented the result. Today I noticed in the testing department that what I've measured doesn't ...
41 views

### What is the difference between residual phase noise and absolute phase noise?

Studying the characteristics of an oscillator with a phase noise analyzer, but I don't quite understand the difference between absolute and residual noise. Any help would be greatly appreciated
28 views

### How can I safely measure the output power of an RFID reader?

I want to measure the output power of a UHF RFID reader. I connected the antenna cable to one of the antenna ports of the RFID reader and to a spectrum analyzer (Hewlett Packard 8568B). There is a 10 ...
75 views

### Can I connect Analog and Digital Voltage Source together?

Is it bad if I connect the A_VDD and D_VDD Pins together if I want to use the same voltage? Or maybe I should ask: Why can I hook up different voltages other than galvanic decoupling? This is the IC I ...
66 views

### Ultracapacitor, capacitance higher than rated?

Broadening my knowledge and experience about ultracapacitors I've made a test bench that was described in here. I've used an IEC methodology to calculate the capacitance:  C = (I_d*t_d) / (\Delta U) ...