Components

Refer to Project 11 for resistor values. Use Project12.mcd to calculate the capacitor value.

Obtain C_f from the square-wave equation

V_s+ is the voltage applied at the noninverting terminal (pin 3) of the opamp, and V_s is the voltage from Chan0_out.

Use T_max = 0.1 S for the intial frequency of f=10 Hz.

Procedure

• Connect the circuit, which includes adding the capacitor and moving Chan1_in to connect to Chan0_out.
  
  
• In the Front Panel of Integrator.vi, set Vs (Chan0_out Peak(V) at 4 V to 10 V. This is adjusted to set the initial peak (lowest frequency) of the triangular wave. Also open subVI, IterateVo.vi, to observe the process of setting the output to near 0 V.
  
  
• Run the VI with the signal set to the SqWave mode. Re-adjust Vs for a value of Vo(Peak-to-Peak) (init) of between 5 V and 6 V. Verify that the initial and final peak-to-peak output voltage ratio is approximately 10. Note that it will be less than 10 due to the finite R_fC_f The ideal integrator has infinite R_f. Note that only the last half of the output array is used in the output voltage peak determination, to avoid initial transients. Also, the average value of the output voltage channel is subtracted from the waveform in the oscilloscope. Obtain a log of the Front Panel. Default and save.
  
  
• Now set the input waveform switch to Sine-wave and re-run. Note the lower peak value. Obtain a log of the Front Panel.