122-28176 Parallax Inc, 122-28176 Datasheet - Page 184

• 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

The gain formula for this configuration is:
or
If the input increases to 3 V, the output will decrease to −3 V. The output is inverted
from the input. Note the supply voltage: +12 V and −12 V. Unlike previous circuits, this
one requires a negative supply because the output must go negative. Not all op-amps are
the same! Many op-amps require a dual supply, or + and − supply voltages, such as the
popular LM741. The LM358 was chosen for this text because it requires only a single
supply, or +voltage and ground.
One final op-amp configuration to consider is the differential amplifier in Figure 5-28. In
this configuration, neither input is ground. The output is dependent on the difference
between inputs.
The direction of the output relies on the principle of balancing inputs. If the inverting
input is higher than the non-inverting input (V
attempt to drive down voltage. If V
V
I1
. The resistor networks of both sides must be equally sized.
AV = −R
V
V
O
O
= −2 V
= (−1)(V
= (−1)(2 V)(10 kΩ/10 kΩ)
f
/R
i
I
)(R
f
/R
i
)
I2
< V
I1
, the output will be positive to drive V
I2
>V
I1
), the output will go negative in an
Figure 5-28
Example of
Differential Amplifier
configuration
DO NOT BUILD
I2
up to