Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [precision]

Use this tag to indicate that the topic is related to achieving the highest precision for a circuit. Examples include using 1% resistors instead of 5% or 10%. This tag also can be used in relation to measuring precision in a finished circuit.

Use this tag to indicate that the topic is related to achieving the highest precision for a circuit. Examples include using 1% resistors instead of 5% or 10%. This tag also can be used in relation to measuring precision in a finished circuit.

138 questions
31
votes
6 answers

Why do some EMI/RF shields have holes on the top and some don't?

I am not talking about cutouts for tall components. I don't think they are for ventilation as they are often covered with manufacturer labels.
Dojo
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20
votes
11 answers

Is there a way to average resistors together to get a tighter overall resistance tolerance?

I have a very sensitive, kHz frequency level, application where I need two matched resistors of the same resistance better than 0.05%. Like maybe by one magnitude (0.005%). I am basically needing to match two resistors together so as to form a…
Jirhska
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15
votes
5 answers

Why isn't there any 9.5 digit multimeter or higher?

Why can't you buy a 91⁄2-digit multimeter? Isn't there any need for it? Is a 81⁄2-digit multimeter the latest high end you can buy? I have tried Keysight, Keithley, and Fluke, but there is nothing higher than 81⁄2 digits.
voltage_drop
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13
votes
5 answers

op amp+mosfet = current source.Why do we need a feedback resistor?

The feedback resistor is needed to compensate for the error of the input currents? How to choose the resistance R2. Circuit source Resistor R2. Can I use this circuit, op-amp with differential input voltage range = +/- 0.6V? I'm not sure. I think…
AndreyB
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12
votes
5 answers

What is the difference between high precision resistors and current sense resistors

Actually, I am trying to build a current monitor for a wireless sensor network. I am going to use a current sense resistor as the current will pass through the resistor. By measuring the value of the voltage, the current value can be calculated. My…
Sabir Moglad
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11
votes
3 answers

Very high precision zero crossing detection

I have a setup that is equivalent to a guitar string with pickup, with signals of similar frequency range. I have a simple zero crossing detector with a comparator and then just count the interval between low-to-high transitions using a…
TrivialCase
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11
votes
2 answers

Should we use wheatstone bridges nowadays?

For measuring strain gauges, the Wheatstone bridge is the historical choice. In a quarter Wheatstone brigde (\$350 \Omega \$ typically (?)), with a high input impedance amplifier, and some bridge power voltage \$V\$, the ratio between the bridge…
Brethlosze
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11
votes
1 answer

How does the CMRR of difference amplifier ICs change over time?

When designing precision analog circuits, I often come across parts which seem to be more than accurate enough for my purposes, but where the datasheet does not specify how key parameters will change over time. Right now, I am looking at datasheets…
Medo42
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10
votes
8 answers

*Very* high precision, *very* stable current source

My background: experimental physics. Not an electrical engineer, but I have some experience putting together basic electronic circuits for physics experiments. So please be kind and explain as if I'm a noob. Thank you! What I'm trying to do: A very…
ugachmaaz
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9
votes
2 answers

Mounting DIL8 package on SO8 footprint

As you might know, it is hard to get components these days. That's why we engineers have to get creative sometimes ;-) The company I'm working for has a shortage of a Zener-type voltage reference which comes in a SO8 package. We have found about…
Stefan Wyss
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9
votes
5 answers

Measuring temperature with ±0.01°C accuracy

What is the most accurate way to measure temperature to ±0.01 °C? I have looked into using a Wheatstone bridge (with a minipot for minor calibrations) and an RTD for its precision and range. I need a range of -85 °C to 55 °C. Ideally this would…
Yisonco stellargold
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8
votes
3 answers

Accuracy vs Precision

Does it ever make sense to have more precision than accuracy? E.g. if you had a variable resistor which you could control with a resolution of 0.01 ohms but your multimeter only had 1% accuracy, then that extra resolution would be pretty useless…
jrandj
  • 105
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8
votes
1 answer

Parallelizing op-amps for higher precision

Is there a known way to parallelize op-amps for higher precision? Say, for example, I have a typical op-amp driving a MOSFET as a follower: Now, for the sake of the argument, on average, the NMOS is only accurate down to millivolts and starts being…
Tempus Nomen
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7
votes
2 answers

What are the effects we need to consider when transmitting extra low voltage (0.1 uV) signal over ~1m long cable?

What are the effects we need to consider when transmitting extra low voltage (0.1 uV) signal over about 1 meter of cable, either coaxial or shielded twisted pair ? The source is low impedance (~5 ohm), and the receiver would be high impedance…
vadimus
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6
votes
4 answers

I'd like to request a review/bashing of this circuit for a high precision soil moisture sensing and analysis device. Where did I go wrong?

Below you will find a buffet of questions and the schematic for my device. (Click on it and you will get the full-size image.) Please tear this up. I'm a self-taught novice putting together a high-precision device. Can you help me validate the…
Tim Cerka
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