Signal conditioning circuits (CAS) with operational amplifier

Signal conditioning circuits (CAS) with operational amplifier

CAS signal conditioning circuits with operational amplifier

A signal conditioning circuit allows adapting the input levels of a signal to other levels of voltages, so that these signals can be acquired in the next stage of the circuit that is designed:

The best way to explain is with an example:

It is desired that an input of a sensor Lm335 (10mv / ° C) sensor range -10 to 100 ° C

Work from 0 ° C to 50 ° C

That is 0 ° C output 0 Volts

And at 50 ° C output 5 Volts

The sensor delivers to:

0 ° C --------> a voltage of 2.73v

50 ° C --------> a voltage of 3.23v

Step 1. Draw a graph where the desired output is observed.

We can observe two pairs of points in the graph

Table 1. Points of the graph

	Entry (X)	Output (Y)
Initial Point	2.73	0
final point	3.23	5

Step 2. How do you want a linear output? This means that the previous graph is the graph of a line. Therefore we can find the slope (m) with the equation (1), where the output is (Y) and the input (X)

Now replacing in equation (1) the data of table 1.

Step 3. We use equation (1) to find the equation of the line.

Now we replace the initial values ​​in equation (2) and the value of the slope

This means Y is the output of the operational and X the sensor input

Step 4. We use Operational Amplifier in adder configuration