Operational Amplifiers

The idea behind the op amps lab is to apply operational amplifiers in a real world scenario. There may be many instances in the real world where a circuit may be required to have a different set of voltages at different parts of it. For example, a sensor which captures certain information may not be outputting an ideal voltage for it to work with the attached processing unit. Enter the Op Amp which can make it work! The following circuit was built and all the values were recorded.

Once the circuit was constructed, it was apparent that the circuit contains a feedback loop. By putting a resistor in between the output voltage and the input voltage, the operation amplifier can be made to output the desired voltage gain.

Given

  V1 = 12.13V

  V2 =  12.06V                                                                          

 Result

   Ri = 1K Ω     Rf = 10KΩ

     Rx = 1152 Ω       Ry= 104.7 Ω

Vin (V)	Vout (V)	GAIN	VRi (V)	IRi (uA)	VRf (V)
0	-0.05	0	0.007	7.00	0.06
0.25	-2.54	-10.16	0.269	269	2.57
0.50	-5.08	-10.17	0.536	536	5.12
0.75	-7.56	-10.08	0.797	797	7.62
1.00	-9.91	-9.91	0.946	946	9.91

The power supply current

Iv1=2.32mA

Iv2=1.49mA

Pv1= 12.13*2.32m=28.14mw; Pv2= 12.06*1.49m=17.97mw which satisfy the power supply constraint to supply no more than 30mW each. It came out that the current being drawn from sources were about 7.5 and 1.8 milliamps. These were not expected but that may be in part due to the fact that the power supplies (voltage supplies) were also being used to power the voltage dividers.