Experiment #3 Filters and Amplifiers

 Objective:

This lab introduces students to electrical filters and amplifiers by using automated systems board with NI ELVIS III. Then, students can build filtering and amplifier systems on the protoboard, figure out input-output relations of such systems with active electronic elements.

1. Theory Overview

Filter circuits play an important role in many electronics designs. They are primarily used to pass desired signals while blocking unwanted signals, based on their frequency characteristics. Filters behave differently with signals of different frequencies and can affect the different components of our signal. For example, if our measurement is made up of a 10mV 1kHz signal wave combined with a 5mV 60Hz noise component, a filter could attenuate only one of those components and leave the other.

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The switch in the amplifier is software controlled. Closing and opening the switch yields two different possible gains.

2. Pre-Lab Quiz

• Quiz Date: xxxxxx

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3. Experimental Procedure

Before programming with the NI ELVIS III, you must first create an NI ELVIS III project. With an NI ELVIS III project, you can group together all the files relevant to your application and run VIs on the NI ELVIS III.

Safety

Be aware of powering the NI board and be aware of not creating any short circuit on the board (connecting ground and power levels (+5V, 3.3V) is not recommended, and may create some damage on the electronic components, be careful about that.)

Hardware/Software Equipment Check

Prior to starting the lab, make sure the equipment is working by conducting the following steps:

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Step 2:   Make sure that you press the open button on the device.

3. Data Collection

Part 1 Low Pass Filter

In this experiment, you will use your NI Automated Measurements Board and LabVIEW to conduct measurements on a basic low pass filter. You will measure the stimulus voltage and compare it to the filtered voltage, for different frequencies of input.

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1. Non-Inverting Amplifier

   Launch Instructions:

   • Connect both the output channel A/AO0 and A/AI0 to the input socket of the non-inverting amplifier (socket 15) on your measurement board. Note: The stimulus signal generated from channel A/AO0 is fed through the input of the amplifier. The same signal is read from the amplifier input using into channel A/AI0. This serves the dual purpose of generating the signal we want to pass through the amplifier on the board and reading that signal back into the NI ELVIS III to programmatically display it.

   • Connect B/AI0 to the output socket of the non-inverting amplifier (socket 16).

   • Connect AMP to analog ground.

   

   Run the main VI and from the amplifier configuration dropdown list, choose non-inverting amplifier x2 (low gain).

   

5. Post-Lab Report

• Due Date: xxxxxx

The report for Procedure 1 is expected to include:

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