Tagged Questions

2
votes
2answers
91 views

Op-amp input stage for Arduino Due ADC - guitar signal

I am trying to design an op-amp input stage to capture a guitar through an ADC, specifically the ADC on an Arduino Due (3.3V, 12 bit). I am aware there are numerous ways to configure and bias the ...
6
votes
1answer
240 views

Adjusting offset (and possibly gain) of ADC preamp OPAMP with DAC

I am designing simple 200MHz scope for use with FPGA board and came up to idea of software adjustable offset and gain of input preamplifier. It is using TI ADC08200 and since I am not much ...
1
vote
2answers
551 views

Negative Voltage Level Shifting to an ADC

I am currently building a project that uses an AD595 analog devices chip to linearize the output of the Thermocouple sensor to 10mv/deg C. This output is to be connected to the ADC input of a Zigbee ...
2
votes
4answers
330 views

How to shift differential signal to read with single ended adc?

I'm using a current sense resistor (0.02 ohms) for a high current battery monitor for a hobby project. I'd like to shift this to a 0-5 V range to monitor using an ADC input (single ended.) I ...
1
vote
1answer
172 views

op-amp + ADC slow reaction

I have the following schematics: If I have a scope probe on VIN, everything works very well. VIN is an amplification of the input and the ADC reports it very well: good accuracy and no delay. But ...
4
votes
1answer
902 views

Amplifying RTD signal to fit ADC range

I'm trying to hook up my 3 wire PT100 RTD probe to an Arduino, but end up out of my depth when it comes to the whole op amp circuit design. I have stolen the 1mA current source and wire compensation ...
4
votes
1answer
245 views

Input stage for ADC with operational amplifier

I am trying to make a voltmeter with a 10-bit ADC. The ADC can measure only positive voltages so I have made an input stage with Operational Amplifiers. The idea of the circuit is to transform any ...
3
votes
1answer
450 views

Drift and “flipping” in Instrumentation Amplifier reading thermistor

Disclaimer: I only have about 2-3 months of semi-intensive electronics experience. Note that the chip (to the left of the Arduino, is Analog Digital's AD623 Instrumentation Amplifier) Datasheet ...
3
votes
4answers
890 views

What is the purpose of this op amp?

I am trying to build a pH meter using the below circuit. I am trying to understand the function of Op Amp U1. As I understand it, the LM4140A-1.0 is a voltage reference outputting 1.024V, which is ...
3
votes
2answers
404 views

Can I provide a negative input voltage to this (or any) ADC?

I have a pH probe which is a high impedance voltage source of which I want to measure in increments of 0.5mV (500uV) with an ADC. This voltage can swing between +/- 1V. I have chosen this ADC as ...
5
votes
3answers
7k views

How to make a clean amplified microphone analog to digital conversion?

I've asked a couple of questions relating to this project the past couple of days, but I cant seem to put it all together. I hooked up an electret mic into an opamp and gave output to my arduino ...
1
vote
6answers
759 views

Scaling analog signal before ADC: A low cost, low pin and component count solution

Extending the question: Scaling Voltage for Arduino Analog In, Beyond Voltage Dividers Making a simple digital thermometer. Ideally, my circuit will only need a 3.3v supply. The sampling will be by a ...
6
votes
6answers
2k views

How do I sample a -2 V to +2 V analog signal with a PIC microcontroller?

I am using a PIC micro with a 10bit ADC to take readings from an analog signal with a frequency less than 300 hz. However that analog signal is in the range of -2 V and +2 V. How can I condition the ...