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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.

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How to make an ideal rectifier which can efficiently rectify 3 phase AC for power applications? [closed]

I'm working on a wind turbine project which needs to be able to rectify 3 phase AC with varying voltages. The lowest the input voltage will likely be is 2V, while the higher end will be 27V. I've been ...
soconnoriv's user avatar
2 votes
2 answers
208 views

External DAC (DAC8568) software calibration

I'm using a 16-bit 8-channel DAC (DAC8568), driven by STM32 MCU. I need to obtain the 0-5V and 0-10V switchable output range, so to achieve that the voltage must be amplified with op-amp. This raises ...
coldmind's user avatar
0 votes
3 answers
119 views

Load regulation of constant current source

LM317HV data sheet provides following reference circuit for use as a "simple, fixed-current regulator" in section 9.2.9. It also specifies typical load regulation of 0.1%. I don't think the ...
beardeadclown's user avatar
0 votes
1 answer
79 views

Right transimpedence amplifier choice for input range

I have a device that produces a ±30 nA signal and I'd like to measure this to a 0.1 nA precision. Since the currents are so low and I don't have much time to make mistakes, I am planning to use a TIA ...
JoVi's user avatar
  • 1
3 votes
1 answer
194 views

What is more precise: using an op-amp or internal PGA of an ADC to amplify a low-voltage signal?

I'm wanting to current sense a 10A load with high precision. I'm planning to use a current shunt resistor and then amplify/filter this signal before sending it to an ADC. Which design flow is ...
ken's user avatar
  • 31
2 votes
0 answers
87 views

Voltage-controlled pulse width modulator (PWM) LTC6992 accuracy [closed]

I have to design a voltage sensor for sensing 4000 V highly precisely and for making the PWM. I was surveying the LTC6992. It is simple and quiet, easy to implement, but there is a problem with its ...
Farzaneh's user avatar
  • 159
3 votes
3 answers
546 views

Is there a specific definition for the tolerance value of a resistor?

Is there any authoritative definition for what the tolerance value of a resistor actually specifies, or is it just a de-facto common understanding, or are the details left up to individual ...
epiii2's user avatar
  • 33
0 votes
1 answer
176 views

Transimpedance amplifier maximum current resolution

Maybe this question is a bit too general but I don't seem to find any solution. I want to build a current sensor for a current that ranges from 1uA to 1mA and needs resolutions of nearly 1pA. I know ...
Weijie Chen's user avatar
2 votes
1 answer
342 views

Low noise virtual ground, voltage reference or LDO + op amp?

I'm doing some sensitive signal measurements in 1~10kHz range where I amplify and filter (multiple active stages) a small voltage signal by hundreds ~ thousands of times and then sample it. A negative,...
Wjx's user avatar
  • 185
6 votes
4 answers
985 views

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-...
Tim Cerka's user avatar
  • 109
1 vote
3 answers
323 views

The most precise resistor with respect to temperature ppm

What is the most precise resistor available (measured in terms of ppm drift if measurements are repeated over time)? I just want a passive box with two terminals. The temperature will be kept between ...
bobuhito's user avatar
  • 554
1 vote
1 answer
389 views

3 wire RTD configuration Wheatstone bridge Vs. Constant Current Source

I am trying to design a 3 wire RTD circuit. I've been looking into either a Wheatstone bridge or a constant current source with ratiometric measurements. I would like to know which is the better ...
UKNP's user avatar
  • 11
3 votes
1 answer
333 views

Negative pulse at NPN collector when base switches off and reverse-active mode behaves better at HF

I have a system that detects pulses amplitudes with a peak detector, the signal from which is then digitized with an ADC. Pulses can sometimes overlap, so I've decided to "zero" the peak ...
sx107's user avatar
  • 1,109
2 votes
0 answers
60 views

Verifying the Measurement Precision of a Circuit

My aim is to build an electronic circuit that allows me to measure the relative precision of the energy of optical pulses in the order of 10^-6. The optical power of the laser pulses is measured with ...
quaser78's user avatar
2 votes
2 answers
71 views

Ideas for measuring the position of a card in a bus (through hardware)

I am looking for ideas on how to detect the bus position of a module (PCB card) when they stack up. I am designing a PCB module that is going to be controlled and connected to a carrier board. This ...
Kike Rueda's user avatar
8 votes
1 answer
910 views

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 ...
Tempus Nomen's user avatar
0 votes
0 answers
132 views

Why does oscilloscope high-resolution mode for acquisition show inconsistent measurements?

Question: Why I get inconsistent measurements from scope specifically in high resolution mode, i. At cold start higher values are obtained, as time passes measurements drift (gets lesser values) ii. ...
Khalil's user avatar
  • 1
9 votes
2 answers
576 views

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 ...
Stefan Wyss's user avatar
  • 7,653
3 votes
1 answer
211 views

Noise of a precision/active rectifier

I am trying to build a precision rectifier circuit to implement AM demodulation in a sensor signal chain. For now I have calculated the sum RMS noise of the total signal chain except that of the ...
Stanley's user avatar
  • 31
0 votes
2 answers
124 views

Opamp output clamp

During power-up, U2A's voltage will be undefined. I would therefore like to clamp it with a relay. Additionally, U2A is buffering a voltage from a 20-bit DAC -- therefore I need to care about thermal ...
Evan's user avatar
  • 359
0 votes
4 answers
475 views

Measure capacitors in parallel and series to increase precision?

I measure a capacitor \$C_1\$ with an instrument that has a tolerance of measurement \$\pm 5\%.\$ I do the same with another cap \$C_2\$. Then I put \$C_1\$ and \$C_2\$ in parallel (values add up) and ...
Niculae George Razvan's user avatar
2 votes
3 answers
522 views

Sigma-Delta differential ADC for PT100 without precision Iexc or Vexc

We are discussing a way to precisely measure PT100 (variable resistance) using a MSP430 with 24bit sigma-delta differential ADCs without having a precision source of current or voltage. We came up ...
MarcelH's user avatar
  • 50
1 vote
2 answers
79 views

Options for tracking upsets in very fine movements

I'm working on a small engraving device that sometimes hits a tougher part of the target material. Since the tip is very small and spins at a high speed, the engraver sometimes involuntarily slides ...
user35443's user avatar
  • 149
-1 votes
1 answer
103 views

Choosing transformer for precision power supply design [closed]

I am trying to figure out what specification transformer I need to design a linear precision power supply which has 3 channels operation with certain requirements. All the 3 channels have total power ...
Roger Dsuza's user avatar
2 votes
3 answers
89 views

Low spread high power laser

I am looking for a laser which can travel about 10 km through air from one end of a lake to another. It needs to have a minimal spread, i.e. a small diameter spread over the 10 km - less than 10 cm ...
user813801's user avatar
2 votes
2 answers
1k views

Precision current source 1 nA circuit analysis

I couldn't find any detail explaining this circuit. How would I change it to make it operate between 1 uA to few microamps? Would change 10 Mohm to 10 kohm would greatly degrade the performance? I can ...
Betty Sammy's user avatar
1 vote
0 answers
120 views

MUX Pulldown resistor Questions

I have a precision application where I am demodulating two sine waves using an analog mux (ADG613) and then Low pass filter to measure it's amplitude. The ADG613 is a 1:4 MUX made into a DPDT (chosen ...
Josh Girgis's user avatar
0 votes
2 answers
729 views

creating a differential amplifier for low voltages (current shunt)

I'm trying to create a "precision" fully differential amplification stage, to measure uA on a 10R shunt, and mA on a 0.01R shunt. shunt resistance values are set at those values for burden ...
super7800's user avatar
1 vote
0 answers
67 views

Active voltage limit circuit

In my application there is a signal from 0-10V. The signal gets into 4 different OPAMPs with different gains which are supplied from +- 5V. I would like to limit the input voltage to the OPAMP to 0-2....
Pelegk's user avatar
  • 11
0 votes
0 answers
38 views

MEMS-FPI tunable filter

I've got to control a tunable filter on a MEMS-FPI C14273 IR sensor. It works by inputing a voltage on a range from 25 to 48 V, wich makes the lens move. It needs to be precise because if i go over ...
Simon Janelle-Bombardier's user avatar
1 vote
1 answer
89 views

How do I deal with Seebeck Effect while measuring resistance with 4-lead ohmmeter?

I'm trying to measure the DC resistance of an inductor I made out of AWG 11 wire. From my calculations its impedance should be around 0.0012 ohm, and the ohmmeter measured precisely 0.0012 ohm. But ...
user2934303's user avatar
20 votes
11 answers
6k views

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 ...
Josh Girgis's user avatar
2 votes
1 answer
160 views

Op Amp Selection Help for Rail/ Rail IO

I am looking for an operational amplifier which will fit my requirements. My circuit consists of two cascaded non-inverting amplifiers.I have a classical non-inverting setup.The minus pin of both ...
Eoin O Connell's user avatar
0 votes
3 answers
459 views

Precision amplitude 600kHz square wave generator

I'm looking for a circuit that creates a precision amplitude square wave of 600kHz (50% duty cycle). The amplitude of the square wave needs to be 3Vpk-pk +/-10mV, but can be DC offset. The output of ...
NREX's user avatar
  • 1
0 votes
1 answer
1k views

Input voltage drop in LM358 with "an improved precision rectifier circuit."

I found the input voltage drops around 2V drop (observed from oscilloscope) when I connect the ion mobility spectrometer (IMS) signal to the circuit "an improved precision rectifier circuit",...
Chi-Hsiang's user avatar
0 votes
1 answer
292 views

Floating point representation- Double precision

The difference between 201 and next larger double precision number is 2^P. If IEEE double precision format is used then the value of P is _________? -- I know how number is stored using double ...
Sanjay Verma's user avatar
1 vote
1 answer
1k views

How can I make this Component Tester more accurate?

EDIT: In the answer by Reroute (thank you, Reroute!), he references a very active 253 page EEVblog topic -- $20 LCR ESR Transistor checker project that probably includes exactly what I am seeking. I ...
MicroservicesOnDDD's user avatar
1 vote
3 answers
2k views

Op amp maximum input voltage

Many Precision Rectifier Single Supply Op Amp circuits feed the input AC waveform into the non-inverting (+) terminal of an op amp e.g. see this schematic: Image source: Precision full-wave signal ...
The Answer to Everything's user avatar
0 votes
1 answer
239 views

Bit growth handling for complex multiplier using Gauss' method

I'm trying to predict/handle the bit growth that occurs when implementing a complex multiplier using Gauss' method. I am looking to implement this multiplier in VHDL. The FPGA I use has a limited ...
Fo0ty's user avatar
  • 3
0 votes
3 answers
527 views

Arduino frequency measurement to 2 or 3 decimal places

I am in the process of building a Proton Precession Magnetometer to calculate the earths magnetic field strength by measuring the precession frequency of protons in distilled water. I am using an ...
Phil Adkins's user avatar
7 votes
2 answers
325 views

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 ...
vadimus's user avatar
  • 83
0 votes
0 answers
117 views

high accuracy analog differential signal switching solutions to prevent distortion (relays?)

first let me define the application and circuit. the application of this is to sence currents ranging from 1nA to around 900mA. to accomplish this two resistors are used, a 10K for the nA range, and a ...
super7800's user avatar
6 votes
2 answers
4k views

mV variations even with a simple voltage divider

edit: After using a prototype pcb instead of breadboard, placing all possible electromagnetic sources away and unplugging all the equipment from the same line, my noise dropped 2 orders of magnitude. ...
glados's user avatar
  • 81
0 votes
4 answers
1k views

How does oversampling improve the measurement precision?

Regarding improving the precision of a measurement, I have heard that a measurement precision can be improved by filtering or oversampling. When I think of filtering I can make sense because ...
user1245's user avatar
  • 4,333
4 votes
4 answers
456 views

Confused with the effect number of decimals at the output of transducer

There is an ultrasonic device which measures and outputs both wind speed and direction and has a very long manual. But to keep it short and summarize, the accuracy and the resolution for the wind ...
ty_1917's user avatar
  • 1,016
0 votes
2 answers
382 views

Use a precision opamps or instrumentation amplifier for load cell application

I'm making a low power weighing scale with good precision. I'm contemplating if it'll be better to build a instrumentation amplifier with discrete OPAMPs of LPV821 which is low power (Iq 650 nA), high ...
EarthLord's user avatar
  • 597
0 votes
1 answer
588 views

Questions about LM741 in an ECG Circuit Schematic

I'm doing an ECG circuit in which I want to use LM741 for active filters and the Right Leg Driver. Basically I will change the LT1007 in the schematic I used for simulations above with LM741 in real ...
D M's user avatar
  • 1
11 votes
3 answers
3k views

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 ...
TrivialCase's user avatar
0 votes
1 answer
167 views

How to obtain a high precision mV signal within a specific interval using a variable resistor?

I want to design a circuit which outputs a signal ranging from 0-70 mV using a variable resistor ranging from 80.51 Ohm - 183.05 Ohm and a supply voltage of 12 V. My idea so far has been to make a ...
Lord CH's user avatar
12 votes
2 answers
2k views

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 ...
Brethlosze's user avatar
  • 1,427