122-28176 Parallax Inc, 122-28176 Datasheet - Page 206

• Manufacturer Part Number: 122-28176
• Description: GUIDE STUDENT PROCESS CONTROL
• Manufacturer: Parallax Inc

Specifications of 122-28176

• Accessory Type: Manual
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Testing it out with a voltage of 1.2 V at V
Of course, accomplishing this requires supply voltages in excess of +/− 12 V for the op-
amps. Another option is to offset the input prior to amplifying the voltage.
Consider the differential amplifier in Figure 6-11.
amplifies the difference between the two input voltages.
The formula for this configuration is:
where V
voltage of 1.2V from the sensor, relating to a temperature of 120 °F:
Figure 6-10 Amplify and Offset Signal with Op-Amps (DO NOT BUILD)
Stage 1: −10(1.2 V) = −12 V
Stage 2: −(−12 V) − 7 V = 5 V
V
V
V
I1
O
O
ADC
is the voltage from the LM34 and V
= 10(V
= (V
= (1.2 V − 0.7 V)(100 kΩ/10 kΩ) = (0.5 V)(10) = 5 V
I1
−V
I
− 0.7)
I2
)(R
f
/R
i
)
I
representing 120 °F:
I2
is the offset voltage of 0.7 V. For the
Recall that this configuration