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| university:courses:alm1k:alm-lab-phase-split [10 Jun 2016 17:20] – [Directions:] Doug Mercer | university:courses:alm1k:alm-lab-phase-split [29 Aug 2019 19:59] – [Directions:] Doug Mercer |
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| The breadboard connections are shown in figure 1. The single transistor combines common-emitter and emitter follower configurations to provide two equal amplitude, opposite phase outputs. By choosing R<sub>C</sub> = R<sub>E</sub> (and both much less than r<sub>E</sub>), the absolute gain to each output is 1, but the collector and emitter voltages will vary out of phase with each other. Shown here using the single (+5 V) power supply, the voltage swing from either output can nearly reach one half of the power supply p-p as the transistor operating condition varies from cutoff to saturation. Of course, the base bias voltage ( DC offset of CH-A output ) must be chosen to set the base voltage swing to be between a little more than + V<sub>BE</sub> of Q<sub>1</sub> and one half of the power supply ( 2.5V ) + V<sub>BE</sub>. | The breadboard connections are shown in figure 1. The single transistor combines common-emitter and emitter follower configurations to provide two equal amplitude, opposite phase outputs. By choosing R<sub>C</sub> = R<sub>E</sub> (and both much less than r<sub>E</sub>), the absolute gain to each output is 1, but the collector and emitter voltages will vary out of phase with each other. Shown here using the single (+5 V) power supply, the voltage swing from either output can nearly reach one half of the power supply p-p as the transistor operating condition varies from cutoff to saturation. Of course, the base bias voltage ( DC offset of CH-A output ) must be chosen to set the base voltage swing to be between a little more than + V<sub>BE</sub> of Q<sub>1</sub> and one half of the power supply ( 2.5V ) + V<sub>BE</sub>. |
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| {{ :university:courses:alm1k:alm-lab-phase-split_f1.png?500 |}} | {{ :university:courses:alm1k:alm-lab-phase-split_f1.png?400 |}} |
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| <WRAP centeralign>Figure 1, Phase splitter. Outputs are 180° out of phase.</WRAP> | <WRAP centeralign>Figure 1, Phase splitter. Outputs are 180° out of phase.</WRAP> |
| ====Hardware Setup:==== | ====Hardware Setup:==== |
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| The channel A voltage generator should be configured for a 500 Hz Sine wave with the Max value set to approximately 2.5 V + V<sub>BE</sub> and the Min value set to approximately +V<sub>BE</sub>. The channel B scope input, CB-H, is used to measure either the voltage at the emitter or the voltage at the collector. To measure the input to output gain compare the CB p-p measurements at the emitter and collector to the CA p-p measurement. Use the SnaptShot function to save and display a copy of one output while observing the other. | The CH A AWG generator should be configured for a 500 Hz Sine Shape with the Max value set to approximately 2.5 V + VBE and the Min value set to approximately +VBE. AWG channel A should be set to SVMI, Split I/O Mode and the AWG B channels should also be in Split I/O Mode (SVMI or Hi-Z does not matter in this case). The AIN and BIN input pins, are used to measure the voltage at the emitter or the voltage at the collector. To also display the AWG channel A output waveform we can use the X Math trace. From the Curves drop down menu select CA-V, CB-V and X Math traces. Open the Math controls screen and enter AWGAwaveform[t] in the X Math Formula entry. The Units can be V and the X Axis can be V-A. |
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| | To measure the input to output gain compare the p-p voltage measurements at the emitter and collector to the AWG A p-p setting (Max – Min). You can also display the differential voltage (DC part cancels) between the two outputs by clicking on the CBV-CAV Built In Expression on the Math controls. |
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| | Be sure to save a copy of the scope screen to be included in your lab report. |
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| | {{ :university:courses:alm1k:alm-lab-phase-split_f4.png?600 |}} |
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| | <WRAP centeralign>Phase splitter. Outputs at emitter and collector are 180° out of phase.</WRAP> |
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| ====Procedure:==== | ====Procedure:==== |
| **For Further Reading:** | **For Further Reading:** |
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| https://en.wikipedia.org/wiki/Phase_splitter | [[wp>Phase_splitter|Phase splitter]] |
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| **Return to Lab Activity [[university:courses:alm1k:alm-labs-list|Table of Contents]]** | **Return to Lab Activity [[university:courses:alm1k:alm-labs-list|Table of Contents]]** |
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