An instrumentation amplifier (InAmp) is an integrated circuit or operational amplifier topology that has high input impedance differential inputs and a low impedance single-sided output. Because of precision laser-trimming techniques for passive circuit elements, InAmps implemented as integrated ...

learn more… | top users | synonyms

0
votes
2answers
16 views

will dual port usb :20 Watt/ 4.2 Amp (10watt.2.1amp each port) provide enough power

im about to get garmin dashcam 20 soon and since it uses your average A-Male to Mini-B cable, i was wondering if i can use my usb car charger i have which has dual ports and i have run out of ...
0
votes
1answer
56 views

Connecting a (small) load cell to Arduino using INA125P

I want to connect the load cell of my (micro) scale to my Arduino. The scale itself is able to weigh max. 800 grams with an accuracy of 0.1 grams - what I want to weigh are loads up to max. 100 grams, ...
4
votes
2answers
38 views

Decreasing ADC Reference vs. Amplifying signal

I have a sensor interfaced to ADC but the Range I am getting is not enough, so now there are 2 options, Gain up the signal or Reduce ADC Gain. But as I heard it, reducing ADC gain will cause more ...
0
votes
0answers
40 views

Design of Capacitive electrodes using Kicad

I am looking into building a capacitive electrode. I find a lot of research papers available online , however none that tell me how to actually construct the capacitive electrode. Most deal with ...
0
votes
1answer
67 views

filters for in-amp, difference amplifier, and non-inverting op amp

I am new to this matter and would like to learn how could I determine the right filters to use for my circuit. I have read some tutorials about active and passive filters but can't get the right ...
0
votes
1answer
69 views

Filtering Noise on Strain Gauge Circuit

I am making a digital weighing scale circuit and currently having difficulties understanding filters that are commonly used to reduce noise in these type of circuits. My load cell is a full-bridge ...
2
votes
2answers
112 views

Why does this analog front end EVM have 4 pins per channel, instead of 2?

Here is a photo of the ADS1299 EVM from texas instruments. It is an 8-channel low noise analog front end chip. I understand that for each channel, the potential difference between plus and minus are ...
3
votes
1answer
82 views

Instrumentation amplifier: resistor to ground for input bias current?

I've inherited an RF amplifier design (50MHz-1GHz) that uses an instrumentation amplifier to accept a DC voltage control signal. Neither myself nor my PI can explain why R8 and R18 are present. My ...
0
votes
2answers
57 views

AD620 in-amp reference pin

I have a weighing scale project using a 200kg load cell with a rated output of 1mV/V. I used 5V as excitation voltage and an Ad620 in-amp for my amplifier. I only need atleast the 0-100kg so I only ...
0
votes
1answer
38 views

MCP6N11 voltage reference and output problem

I am currently trying to setup an instrumentation amplifier and I used MCP6N11. Basically I'm just trying to test the instruamp to output a certain voltage gain before I connect it to my actual ...
0
votes
0answers
56 views

How to wire four half-brige 3-wire strain gauge load cell to an amplifier?

First of all, i am given a task to make a digital weight machine. For this i have chosen 4 strain gauge (3-wire load cell) which you can find here. I have searched all of the links i found on the ...
0
votes
1answer
109 views

using AD620 with load cell

I am currently using an AD620 to amplify the signal coming from my load cell. I am supplying it with single supply of 5V and 0V. Below is my preliminary circuit. I am feeding half the supply to the ...
0
votes
1answer
129 views

AD620 with load cell help!

I have bought a 200kg load cell and an AD620 in-amp. I only want to use 100kg as the maximum weight capacity. I want to power the load cell and the in-amp from the 5v pin of the arduino. The seller ...
5
votes
1answer
185 views

Why is my op-amp chopping up my signal?

I have built an instrumentation amplifier out of two op-amps in a quad op amp (MCP6L04T). The input signal is coming from a low-impedanece source (~17k) and most of the information in that signal is ...
1
vote
4answers
86 views

Using Differential Amplifier to reduce required RC values

I need to implement a low pass filter to convert a 20kHz square wave into a 20kHz sine wave. It would be nice to be able to use lower values, because in CMOS large resistors and capacitors take up ...
0
votes
1answer
54 views

Instrumentation (or diff) Amp saturating when measuring low voltage

I need to measure (amplify) a very low voltage, by low I mean in the order of 20 uV. Right now, using a lab multimeter, I am clearly and repeatably measuring the voltages so I thought that amplifying ...
1
vote
1answer
89 views

Current sensor with instrumentation amplifier (LT1167)

Objective I'm trying to make a current sensor that can accurately measure current up to 5A. In order to do this I'm using an instrumentation amplifier (LT1167) to measure the voltage difference ...
1
vote
0answers
129 views

Problem connecting INA114 with LM331 for voltage to frequency conversion

i'm actually using a load cell and i would like to send the load cell information to an android tablet through jack audio. Then load cell caracteristics are presented here: ...
0
votes
0answers
60 views

Lock-In amplifier

I am currently performing experiments on FM Atomic Spectroscopy. The light from VSCEL is interacting with an akali vapor in a cell and the output is received at the photodetector. The output contains ...
3
votes
1answer
325 views

Why is my instrumentation amplifier's output voltage completely wrong?

I'm trying to amplify the voltage of my load cell (Wheatstone bridge I believe), but my calculated values are not the same as my experimental values. The load cell outputs a differential voltage of ...
0
votes
0answers
54 views

3 wire load cell and ina125p

I'm making a digital weighing scale out of 3-wire load cell. I found in weighing scale which I bought. the load cell has got 3 wires black(B)-red(R)-white(W). the resistance b/w BR,RW and BW was ...
0
votes
2answers
148 views

AD620 voltage noise and ADC SNR calculation

I want to calculate theoretically my effective resolution from C8051F350 in-built sigma delta ADC with different interface options like ISL28134, ADA4528, ADA4898, OPA211, mcp6v07. I want to know ...
3
votes
3answers
141 views

Using step-up converter in metering instrument?

I am designing a pressure calibrator (my first Real project), which is supposed to measure from 0-200.00 mmWC (20000 counts) using Silabs C8051F350 (inbuilt 24-bit Sigma delta ADC). Sensor used is a ...
0
votes
1answer
136 views

Building instrumentation amplifier with resistors and op-amps

According to this question, it is possible to build instrumentation amplifier out of resistors and operational amplifiers. I am more interested in the version where the gain is set by changing Rgain ...
1
vote
1answer
56 views

Questions about the front end design of amplifier circuit

Question 1: Recently, i'm working on a design which needs to design an INA front end. The most used circuit like this (please omit the component values): You see, the two 10M resistors which ...
1
vote
1answer
134 views

What does the feedback capacitor do in Right-Leg-Driver?

It so happens I have seen some people mention about connect a feedback capacitor across the opamp for RLD would improve something better. Can someone capable to explain about the use of the ...
2
votes
2answers
244 views

Understanding load cell and instrumentation amplifier

I want to build a weight scale with 0.1 gram resolution. But I have some problems in my initial stage. I am using a load cell with sensitivity of 1mV/V and excitation voltage of 3 V. With no ...
0
votes
1answer
127 views

Load cell without In-amp

I have a 0-1kg load cell with 4 wires: Excitation + and -, and Signal + and -. I haven't had any problems wiring them up correctly without amplification, and my voltmeter shows me a 1 mV difference ...
0
votes
1answer
182 views

Reading a gas sensor with range from 0 to 60mV with an ADC

I need to take a reading using an ATmega328P of a gas sensor. The ATmega328p has a built in 10bit ADC giving only 1024 'steps' The data sheets for my O2 sensor are: ...
3
votes
4answers
210 views

Type-K Thermocouple interface problems

I'm trying to interface to a type-K thermocouple with an ATXMEGA128A4U and have been experiencing some difficulty and I'm hoping someone can confirm the process I am using. Details.. 1. TC is ...
0
votes
1answer
98 views

Instrumentation Amp problems

I have a 1000 times gain circuit using an INA826: Up to 2mV input 2V out, it works fine, after that point in only gets up to 2.7V. R? is a 6.2kΩ, that brings the 49.9 r to 49.5.
0
votes
2answers
249 views

How to hook up a load cell to an Instrumentation amplifier correctly

I am trying to get load cells connected to an instrumentation amplifier. The load-cells I have are extremely similar to the ones here https://www.sparkfun.com/products/10245. They have 3 wires coming ...
-2
votes
2answers
193 views

Is the supply for a differential op amp compulsory?

Is the supply for a differential op amp compulsory or can we operate those without a supply? I just want to amplify the difference of inputs, I'm not in need of any supply voltage.
4
votes
3answers
323 views

How to set up an experiement to measure SNR for an EEG amplifier?

I have built an EEG amplifier with gain of 2000 and bandwith at 1~40Hz. I use an Instrument Amplifier for pre-Amp and a non-inverting opamp as post-amp and finally bandlimit at 40Hz using a 4th-order ...
0
votes
0answers
75 views

Design an Instrumentation amplifier

I have design an Instrumentation amplifier for a very high sensitivity Load cell. What factors should i consider in selecting the right opamp, resistor values for the In amp. I know that it is ...
0
votes
2answers
106 views

Differential Pressure sensing circuit

I'm trying to understand a differential pressure sensing circuit that I have. Have attached rough design sketch as well. Sensor used is "10 INCH-D1-MV-MINI" by Allsensors. Output span is 20mV for 10" ...
1
vote
1answer
641 views

Voltage ramp in INA125 output

I am using a INA125P to amplify the signal from a beam load cell - and I have noticed a frequent ramp in my INA125P output signal, of about 100mV every 200uS. EDIT: My gain is roughly 800x. I have ...
1
vote
2answers
2k views

Problem of noise with load cell and INA125P + Arduino Uno

I am here with a problem that I cannot solve. Here is the facts : I have a load cell : http://www.robotshop.com/en/micro-load-cell-50-kg.html that I want to use in both direction, so from -30kg to ...
0
votes
1answer
168 views

Instrumentation amplifier for load cells

In the most part of tutorials I see they use INA125 as the instrumentation amplifier for load cells. Is it ok to use another cheaper amplifier as the AD8237? Or is there a specification or ...
1
vote
1answer
2k views

3 wire load sensor connection to INA125P

I am trying to use a 3 wire load sensor, connect it to INA125 for voltage amplification and then use the amplified output to be fed to ADC of Arduino. I had used below configuration with INA125. ...
1
vote
2answers
763 views

Sensing weight with strain gauge, InAmp, ADC & Pi

I have an SEN-10245 sensor for weighing objects (essentially a strain gauge). The goal is to capture data with a Raspberry Pi, so the signal from the weight sensor needs to be amplified and then ran ...
1
vote
1answer
3k views

Hacking a four load sensor based personal weighing scale

I am trying to hack a personal weighing scale.I had taken help of this tutorial but the language used in this is not very easy to understand due to the non-standard naming used for load sensor wires, ...
1
vote
2answers
231 views

Determining correct requirements of Instrumentation Amp in measuring large current shunt

I'm trying to plan out a project of measuring large currents from my car battery through a shunt, and specifically I need help with the INA. I bought this Deltec 250 amp shunt from eBay, that looks ...
2
votes
1answer
402 views

Is it a good idea to make one instrumentation amplifier with three operational amplifiers for thermistor sensing circuits?

Is it a good idea to have those three amplifiers with LM741 Operational amplifier? Has anyone done this so far? I thought of this as this was a cheapest idea. The instrumentation amplifier costs about ...
3
votes
1answer
167 views

Amplification circuit for a limited range of output signals

I have a sensor that puts out a signal between 0 and 25mV. Of that range, I am only interested in the 16mV to 22mV portion. The output should primarily be a DC signal, and the AC response, if any, ...
1
vote
1answer
486 views

ECG Circuit Simulation problems

I'm working on a TINA-TI circuit. I'm no expert in the electronics field or the medical engineering so I am having a hard time figuring out how to construct my ECG circuit. This signal will be ...
1
vote
2answers
139 views

Highly linear amplifier for tiny voltages

I have a tiny voltage which ranges between 0V to 0.05V (bandwidth of this signal is <100kHz) that I need to amplify to 0V to 3.3V. If I would like my final voltage to be distorted only upto 0.5%, ...
0
votes
1answer
91 views

AD623 ANZ vs. BNZ?

I have simulated my first circuit ever and now I wanted to order an Analog AD623 to actually build it. I gathered that I need the 8-DIP package to stick the IC on the breadboard, but there are ...
1
vote
3answers
202 views

Connecting strain gauge output terminals to an instrumentaiton amplifier

Before posing the question the figures are about as follows: In Figure 1 a strain gauge's outputs v1 and v2 is connected to an instrumentation amplifier’s inputs. For simplicity buffering part is ...
4
votes
1answer
93 views

Is an instrumentation amplifier design same with a standard op amp?

Is instrumentation amplifier nothing but a standard op-amp with a different configuration? I wonder if the inner complicated circuit of an instrumentation amplifier same with standard op-amp's. At one ...