Questions tagged [adc]

An ADC is an Analog to Digital Converter. This device converts analog signals into digital form. It is mainly used by the digital circuitry to take analog measurements.

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81 views

Write ADC data to memory and back to DAC (without MCU)

Is there a way that is not too complex way to implement ADC -> SRAM -> DAC data transmission without the usage of the microcontroller? The application is to implement the audio loop of some sort,...
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41 views

Increasing the input impedance of analog input using an op-amp buffer

I'm trying to sample a 0-10V DC voltage as an input to my circuit. I use the following circuit to achieve this: simulate this circuit – Schematic created using CircuitLab The problem I have is ...
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Instrumentation amplifier didn't fix my ADC crosstalk, and I don't understand why

A previous iteration of my circuit was as follows: I am sensing DC voltages across 6 variable resistors (1kΩ Pt RTDs) The 6 resistors are connected in series; the series is connected to a current ...
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69 views

Multiplexing analog signals

I am designing a system to measure voltages from bio-potential sources and feed them into an ADC after filtering and amplification. The source has the following charactristics: amplitudes are in 10's ...
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64 views

Differential amplifier and different ground

I am designing a circuit to measure the voltage across the output of buck converter. With different ground for the buck converter and the micro controller, with respect to which ground will the ADC ...
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19 views

ADC negative input clipping vs scaling and bias

So, I have this differential ADC (AD7641) and plan to use AD8139 as his driver. The goal is to digitize a signal (a sine wave) of about 3.5Vpp and 36KHz. The signal is actually single-ended and ...
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DMA + ADC + FreeRTOS in STM32 - Cannot read any ADC value - Why?

I'm using Nucleo STM32F401RE board. I have a small issue. I have connected SPI connections + two potentiometers and FreeRTOS. But I can't read the ADCs. I wonder why? I have created an array called <...
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49 views

read negative voltage with mcp3008

how can i read a negative voltage by the mcp3008 ? , i tried to do that with this code but i I could not read it , i see that the most readings are 0.00 , this is my code : ...
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Load Cell ADC HX711 Alternatives?

Looking for an HX711 ADC alternative. Sparkfun sells a pricey breakout board with the chip, but I cannot source the IC anywhere online for some reason 🤷‍♂️. Are there any ADCs out there that have a ...
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55 views

Powering multiple ADCs from a single power supply in bipolar mode

I am making a PCB with 10 analog to digital converters, which each ADC needs 5v as analog supply and 10 mA as current. I found a tutorial that uses 2 common 9v batteries for only one ADC for the ...
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128 views

Is this a proper way to find the derivate of a 12-bit ADC?

I'm seeking a solution to find the derivative of an 12-bit ADC. It's for STM32 but let's say it's for likely for an arbitrary micro controller. ...
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37 views

Arduino analogReference() switching during run time

I'm trying to read ADC value off two sensors one that uses 5V as VREF and one that uses the INTERNAL 2.54V as VREF so I use analogReference(); between the reading and it seems to affect the measured ...
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150 views

Why does my sine wave signal look like this with a 20kHz sampling rate?

its been a while. Back at it again with another question. My ADC sampling rate is set to 20kHZ. I took pictures of the ouput DAC at three different frequencies at 770Hz * 2 = 1540Hz (Nyquist ...
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Buffer amplifier, minimizing PCB footprint

I have a circuit that needs to pass 22 analog signals through a buffer amplifier before feeding them into an ADC (due to the relatively high impedance on the analog signals). I plan to use non-...
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What does 0.5lsb and 1.5lsb mean in ADC

Quoted from the ebook Introduction to Microcontroller by Gunther Gridling (pg. 43): The class width of most classes corresponds to 1 lsb, with the exceptions of the first class (0.5 lsb) and the last ...
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AD7705 vs TM7705?

After some research I found the AD7705. To test it I bough two ICs. The ICs cost at least 4USD. The I saw an article about a little PCB with that chip which cost 2USD. https://www.instructables.com/id/...
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Rotary potentiometer nor reading linear

I have a question conserning some strange values I get when sampling a rotary potentiometer using an STM32F103CB MCU. The circuit is as follows: Potentiometer(powered @+5V from a custom PCB) -> ...
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10-bit ADC resolution doubt - 1023 or 1024? ESP8266

I am working with ESP8266 which has a single ADC channel with 10bits and 1V reference. What is the correct resolution in mV/ADC result? 1000mV/1023 or 1000mV/1024? Also, I wonder if the reference of ...
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120 views

How can I prevent my DC-DC converters from exploding?

I'm an electrical engineering student at TAMU working on a project for my first internship: a signal recorder for an experimental helicopter. For context, here are some of my requirements: 19 DC ...
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56 views

What should I do if an ADC is communicating over SPI differently than in the data sheet?

I am trying to get a voltage reading from a MAX1142BCAP+ with a Raspberry Pi 4B. I am just using the default circuit at the bottom of the datasheet and this code for SPI in Python: ...
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measure bipolar sensor signal (±10V) by ADC

I have a continuous bipolar signal that can vary between ±10V and I would like to measure it by ADC. How can I connect it to ADC?
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convert neagative out put signal of sensor to apply adc

I have a problem in convert out of RPM sensor that has -10v - +10v analog output signal. How can I convert the output signal to 0-5v by practical circuit to apply in ADC of micro?
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Is it possible to measure pwm load current using opamp based high side current sensing?

I am referring this app note, hope to use as unidirectional current sensing for a PWM load PWM load - load is a resistor, PWM signal - 100Hz, 150V. Load current 18mA Duty 5% (PWM resolution 8 bit) ...
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47 views

How to improve this circuit design to meet Arduino ADC input impedance requirement?

I have a new pH sensor board, the circuitry looks like this. The Op Amp is operated at 3.3v and the input is "float" to 1.8v with a separate voltage regulator. The output is connected to the ...
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Designing high bandwidth current sensors for inductor current sensing

I am designing a high-frequency current sensor, suitable for sensing +/- 20 Amps at frequencies of 200kHz. This is being used in average current mode control application in an isolated forward ...
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52 views

Converting the 0-10V output of a PMT to a +- 10V dynamic range

I am trying to convert the output of a photomultiplier tube module (Hamamatsu HC120) which ranges from 0 to 10V to +-10V in order to fit the full dynamic range of a ADC (MCC USB-205). To do so, I've ...
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28 views

LTC2311 CMOS SPI connection with STM32

I am currently using LTC2311 as ADC with CMOS setting in my circuit. However, I cannot seem to get any output out in the microcontroller (I use the STM32 Nucleo development board). My question is that ...
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47 views

ADC Measure from source with higher voltage and different ground

I would like to measure the voltage of a battery that varies from 4,5V to 3V. To do so I'm planning to connect this source to a STM32F4 DISCO board and one of its ADCs, which will be set to a VREF+ of ...
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27 views

Programmable sensor signal reference voltage

I'm designing the front-end circuitry for an ADC. The ADC is to be used to read from sensors under two use conditions: An externally referenced sensor, whose signal line will either be 0-5V or ...
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Synchronizing 2 MCU's ADCs over WiFi

I have 2 devices with analog signals. I want to acquire their signal with 2 MCU's (preferably ARM). fully synchronized with the same sampling frequencies, starting and ending simultaneously user ...
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87 views

STM32 HAL_ADC_Start() ends with HAL_ERROR

I'm new to microcontroller programming and I have a problem I can't solve. I am using STM32 Nucleo board L4R5ZI and I try to read the analog value on one of the pins, and then use the ADC to convert ...
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ATMEGA128 & AD7417 Reading first channel using external reference voltage

I'm doing test work in Proteus ISIS. Where in circuit used External ADC, but there is no modeling module in the proteus. And i can't test it. This ADC using TWI(I2C) interface. ADC connection circuit: ...
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PIC MCU: Reliably Capture and Measure Drum Transients with ADC

I'm seeking advice to help my circuit/code/mcu work more reliably and accurately. What I've got right now is almost there, but I'm just missing the know-how to get me consistent readings. I've tried ...
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32 views

Measuring 4-20mA with differential ADC

I have a question. Is it a good way to measuring 4-20mA with differential ADC? Assume that we have a ADC with 2 single ended inputs or 1 differential input. Input A+ is the first input and input A- is ...
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i have two questions about value of adc being changed

I want to acquire the values movement of two strain gauges attached to dc motor For example, first strain gauge has values around 10000, the second has 20500 in 0 degree while the first is 10400, the ...
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49 views

Calculating Phase angle from instantaneous voltage

For background info I am an EE/CE that is 10 years out of school and has since worked writing firmware and dealt mostly with digital communications and signals, so now I am having to reach back to my (...
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54 views

using mcp3008I/P adc with raspberrypi

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60 views

Transient Response of AC Coupled Inverting Amplifier

The circuit below is from this App Note. The document describes: The capacitors C1 and C2 need to fully charge for the circuit to function properly. The definition of fully charged can vary depending ...
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31 views

ADC Input Protection with 4-20mA

If you've got a 4-20mA transducer, powered by 14V, and you want to measure it, your analog front end might look something like this: simulate this circuit – Schematic created using CircuitLab .....
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Ambiguity in ADC conversion of analog voltage to digital value

I have question about the common formula used to turn analog input voltage of ADC into an integer binary number that is as bellow : I think that in the equation above N is not integer but floating-...
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1answer
72 views

STM32F429ZI ADC converting too fast

I am trying to trigger ADC1 to convert (for the moment) one channel of a STM32F429ZI microcontroller (on the Nucleo Board) by TIM2 every second. With the code below I configured 180 MHz core frequency,...
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Audio ADC - grounding problem

I searched through the internet but couldn't find an answer to my question. Maybe I just don't know what to search for. I want to convert an audio signal coming from a stage box from analog to digital....
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60 views

Fluctuating ADC results - is it normal and characterized in a datasheet?

As I have been reading [1], there exist four different DAC error types, which contribute to the overall error: Offset Error Gain Error INL Error DNL Error Is my understanding correct, that these are ...
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66 views

Does dividing a clock increase its jitter?

I want to have my microcontroller and ADC using a clock derived from the same source in an effort to avoid intermodulation effects. All clocks are under 50 MHz. The maximum SNR out of an ADC is ...
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70 views

STM32F051 ADC DMA overrun

I am trying to use ADC with 2 channels and DMA, but I only get 1 reading before the overrun bit gets set. Also the 1 reading is wrong, I am expecting a value of approx 2100, but I am getting around 70....
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Trying to interface with intercom / door phone system (Read 15 times)

I have a project idea where I want to interface with my intercom / door phone system. Its a proprietary system developed by SSS Siedle, and there is next to no documentation or research on how these ...
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71 views

RMS calculation in cheap microcontroller

I normally see that RMS calculation is done using some kind of DSP or more high end microcontroller. I'm using this microcontroller and I would like to know if it could do RMS. I need to read 60 Hz ...
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How to increase polling speed of data from external ADC (controller and ADC has SPI interface) without any external interrupt?

I have an an external ADC which has capability to sample data at 40Ksps and controller needs to poll the data from ADC. I am unable to get enough sampling rate by keepon calling it from while(1) loop (...
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46 views

Protecting an ADC from negative voltage: Is it better use diodes OR to offset voltage?

I'm working on a simple guitar amplifier and reader with Arduino. The Arduino will use this input to find the amplitude and frequency of the input signal. I'm getting confused about how the ADC ...
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44 views

Which switch/amplification method described is better for accurate reading of variable voltage using ADC?

I'm trying to design a relatively accurate variable power supply with 2~24V output voltage controlled from an MCU using off-the-shelf parts. For the MCU to be able to read the whole range of voltage,...

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