Tagged Questions

1
vote
1answer
32 views

Thermocouple signal conditioning - how to deal with low output swing margin of amplifier?

I have this thermocouple conditioning circuit. Let's say my gain is 100. Minimum low level for AD8237 is 20mV. As K type thermocouple outputs 40uV per 1C, I will have 4mV per 1 degree C. This ...
1
vote
3answers
79 views

Economical thermocouple amplifier circuit

I'm looking for the most economical circuit that reasonably accurate circuit for amplifying the voltage produced by a thermocouple (so it can be read by an ADC). For the sake of argument, component ...
6
votes
1answer
296 views

Why is my instrumentation amplifier's gain non-linear?

I am using an AD8226 instrumentation amplifier as the pre-amp in a circuit which uses a micro fuel cell oxygen sensor to measure oxygen content in a gas stream. The pre-amp is configured in single ...
1
vote
2answers
139 views

Instrumentation amplifier

I am using an instrumentation amp (http://www.linear.com/product/LT1168), and I am a bit confused why it is giving me a output voltage that I am not expecting. I am pretty sure, I am doing something ...
2
votes
4answers
527 views

Simple op-amp differential amplifier

EDIT: Thanks everyone, I got it to work: Now if only I could accept multiple answers... . . . Is the output of this op-amp circuit linear in input voltage? The last equation \$A = ...
3
votes
3answers
257 views

Very low frequency instrumentation amplifier

I'm trying to choose an instrumentation amplifier for very low frequency signals (seismic monitoring). The trouble I'm finding is that on many of the data sheets, they only give response curves down ...
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 ...
5
votes
3answers
1k views

Op-Amp Input Resistor?

I'm reading through the datasheet for the TL064, which contains this figure on page 16: This is of course an instrumentation amplifier that apparently uses an inverting amplifier's output instead ...
0
votes
2answers
767 views

Strain Gauge with Instrumentation Amplifier question

I have a problem making a circuit like this working I got it from this TI application note. For testing purposes I have set: \$R4=R2=R3=R1=47 \Omega\$ \$ Rf = 10 k\Omega\$ \$Rg= 26.70\Omega\$ ...
2
votes
3answers
351 views

Error in this explanation of instrumentation amplifier?

On this webpage I read an explanation of an instrumentation amplifier: The negative feedback of the top op-amp causes the voltage at Va to be equal to the input voltage V1. Likewise, the ...
9
votes
4answers
2k views

When is it an instrumentation amplifier (In-Amp) and not an operational amplifier (Op-Amp)?

I've seen a number of different configurations for instrumentation amplifiers, including 2 opamp versions. This is also one. But it's just a differential amplifier preceded by input buffers. ...