Questions tagged [measurement]
Measurement is the assignment of numbers to objects or events. All measurements consist of three parts: magnitude, dimensions (units) and uncertainty.
1,169 questions
5 votes
6 answers
1k views
How to measure audio frequency distortion without expensive equipment?
I'm building some BJT amplifiers, and I'm currently getting distortion values via Multisim simulations. However, I'm not fully sure about the results I've been getting, and I would like to double ...
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0 votes
0 answers
30 views
BM2257 Multimeter AutoHold Latching Value Display Time [closed]
±30 counts are equal @ range of 6,000V -> ±30counts x 0.001V = +-0.03V For example if we are at 6 V range and there is a voltage 290 mV (no significant measurement), the AutoHold will not latch/...
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0 votes
2 answers
69 views
BM2257 Multimeter - Significant-measurement in Auto-Hold Function
I have the BM2257 Multimeter and on the manual at page 15 on the AutoHold function it writes the below about Significant-measurements (readings). What means "Significant-measurement"? What ...
- 853
5 votes
1 answer
101 views
Unexpected slope change in I–V curve of an infrared LED — beginner question
I’m a complete beginner working on a simple experiment to measure the I–V characteristics of LEDs. For most visible LEDs, my results look as expected: the current increases exponentially once the ...
7 votes
3 answers
1k views
Can 2-wire measurement reach 4-wire precision?
I recently came across the TIDA-060029 documentation from Texas Instruments (auto-balancing impedance measurement), and I’m not fully sure whether the method used in that design is 2-wire or 4-wire. ...
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10 votes
5 answers
1k views
How can I measure power supply noise and ripple lower than 100µV?
I’m working on a low-noise power supply design and need to verify that its output noise and ripple are below 100µV RMS. However, my oscilloscope has an input noise floor ~500µV RMS, which completely ...
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0 votes
0 answers
79 views
Measuring BJT Gummel Characteristics with Keysight B1500A: Do I Need Three SMUs?
I want to measure the Gummel Plot of a bipolar junction transistor (BJT) using a Keysight B1500A. My setup includes two medium-power SMUs (MP-SMU) and one GNDU. The connections are: emitter → GNDU, ...
- 11
0 votes
2 answers
78 views
Measurement mismatch in star-delta conversion
Recently, I was interested in star-delta conversion formula and I wanted to test it on a 3-phase motor. First, I connected its second terminals together to have star configuration, and I measured each ...
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2 votes
3 answers
146 views
Using a 10k Thermistor Across a Wide Temperature Range to Produce Linear Voltage Change
I have a 1/8 NPT thermistor that will be installed into a oil filter sandwich plate to measure oil temperature. Here is a link to it -> https://www.ebay.com/itm/276877376822 It is a 10k type, but ...
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0 votes
0 answers
56 views
How can I reduce the turn-off spikes in a push-pull converter?
I’ve designed and built a 12V–360V DC-DC converter. The circuit has just been powered up and is under testing. The output is stable at 360V. I had to damp the RCD clamp with an additional RC snubber, ...
- 1,161
2 votes
3 answers
220 views
Strange or normal ohmeter measurements of IRF630 N-channel mosfets
10 new (bought on ebay) IRF630 N-channel mosfets. For all except for one of the 10 mosfets measured the following on an old multimeter on ohms x1k scale which I think uses 9 V battery. Momentarily ...
- 261
5 votes
2 answers
504 views
Is it possible to check the deadtime of a push-pull converter without soldering in the transformer?
I have designed a 12V–360V push-pull converter. I would like to power it up with the least possible risk. I want to make sure that the LM25037 PWM controller and the FET driver circuits are working ...
- 1,161
0 votes
0 answers
121 views
Capacitance measurement using Wheatstone bridge
I want to measure capacitance between 0.5pf and 500pf. Is a Wheatstone bridge a good way to do it? The capacitance is of a twisted pair wire dipped in water for water level measurement. I know I need ...
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1 vote
0 answers
111 views
How do I measure a coax cable’s group delay with a VNA without standing-wave ripples?
Goal I’m trying to get a clean, flat plot of group delay vs. frequency for a coaxial cable so I can derive the propagation speed as a function of frequency. Setup DUT: 10 m RG-58 coax. Instrument: ...
- 11
0 votes
1 answer
61 views
Process Noise Covariance with Kalman Filter : how do you model the process noise assuming it has a non-zero mean error?
Kalman Filter Measurement Offset Error I am attempting to use a Kalman Filter to predict the position of a moving vehicle. One of the instruments I am using to do so is an accelerometer. However, ...
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