Circuit C3 has the input signal applied through the coupling capacitor. Chan0_out V(CCV) provides the input and output circuit bias. The base signal with dc removed is measured again with Chan2_in.
Reconnect the circuit according to Circuit C3. Connect the top of RB to Chan2_out and the bottom of Rs to Chan2_out.
Open SetVCEC3.vi and run to determine circuit bias IC and VCC. Note that if VCC > 10 with VCE < 2 V, a smaller value of RC or larger value of RB is required; that is, there is not a valid solution. (If VCE ≈ 2 V for VCC = 10 V, this is satisfactory.) This situation could occur if the value of βDC used in the resistor design calculation was not representative of the value for your transistor. When the circuit operates properly, default the Front Panel to save the values. This saves a set of variable values for the Mathcad project file.
The VI for the frequency-response measurement is FreqResp.vi (below). The VI sends out a signal through out Chan1_out over the frequency range of) Freq(init) to 1 kHz. The response at the base input node on the source side of the capacitor is measured with in Chan2_in as in Circuit C2.
Open FreqResp.vi and install your value of RC in the Front Panel. Select Vs such as to obtain Vbe ≈ 5m based on Vbe ≈ (rπ/Rs)Vs. Recall that rπ versus current is contained in the data file obtained from Gain.vi and in the Front Panel of Gain.vi. The information should also be saved in the Front Panel of 5ColData.vi.
Open subVI FG1Chan.vi to monitor the waveform of the signal from in Chan2_in. Keep SetVCEC3.vi open to verify that the dc setup functions properly. Note that the dc setup process is configured to be slow to allow the capacitor transient to be completed.
Run FreqResp.vi. Verify that in Chan2_in (ac peak) is about 5 to 10 mV at the highest frequency. Adjust Vs accordingly. Verify that a flat response is obtained at the higher frequencies. If not, a larger capacitor is needed. Default and save the Front Panel to preserve the f3dB information.
From the ProjectC1.llb, open XYToDataFile.vi. Copy and paste the graph data to obtain a frequency-response data set.
