Analog Circuit Design Laboratory Report - MyWeb at WIT ...

Roff was calculated to be a 1.2-MΩ resistor and a 1-MΩ potentiometer in series with a
Vref of +15V.
After the circuit was constructed the gain and offset adjustments were calibrated
using the potentiometers so that at 5 Lbs the DMM read 5V and at 0 Lbs the DMM read
0V. The circuit was then tested for a weight of 1250 grams. A value of 2.74V was
calculated and a value of 2.74V was measured at this weight.
Conclusion:
In the op amp’s simplest form, the output voltage will be at ±Vsat. The voltage output is
determined by the polarity of the differential voltage across the input terminal. For either
differential voltage polarity, the magnitude of VO will be approximately1V less than the
power supply voltage, either VCC or VEE. This was demonstrated when the VCC of +15V
was connected to pin 3. VO was measured at an acceptable value for +Vsat at +14.3V.
Then, when the VEE of -15V was connected to pin 3, the VO was measured at an
acceptable value for -Vsat at -13.63V. Supply current was measured as 0.66mA. This
was not equal to the typical manufacturer specification of 1.7mA, but this is considered
beneficial as it allows the op amp to operate at a lower temperature. This op amp
configuration was also generated in PSpice having the non-inverting pin take the different
supply voltage sources. This gave values that were similar to the measured values.
With a typical resistance value of 10-kΩ connected to the output terminal of the
op amp, a load current is drawn from op amp. This load current varies with the magnitude
of the load resistance. The maximum load current, known as the short circuit current is
typically 25mA. For the op amp tested, the short circuit current was 27mA. Short circuit
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