PASCO WA-9867 Instruction Manual

Sine wave generator

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No. 012-08678A

Sample Data

Sine Wave Generator

WA-9867

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Page 1 Instructions Instruction Manual Demonstrations Experiments No. 012-08678A Sample Data Sine Wave Generator WA-9867...
Page 2: Table Of Contents
Sine Wave Generator Model No. WA-9867 Contents Introduction..............3 Setup .
Page 3: Introduction
Banana Patch Cords SE-7123 Introduction The PASCO Sine Wave Generator supplies adjustable-frequency AC power for applications such as driving speakers, wave drivers and string vibrators. The digital display and easy-to-use frequency and amplitude controls make this unit ideal for student labs.
Page 4: Setup
Sine Wave Generator Setup On/Off Output Jacks Switch Power Input Display Increment Keys Course Frequency Fine Frequency Amplitude Knob Knob Knob Setup Input Power Connect the included power supply to the power input of the Sine Wave Generator. Slide the ON/OFF switch to the right to turn it on.
Page 5: Operation
Model No. WA-9867 Operation Operation In addition to the description given here, there is a complete operational flow chart on page 10. Manual Control Amplitude Adjust the amplitude of the output signal with the Amplitude knob. The amplitude range is approximately 0 V to 10 V.
Page 6 Sine Wave Generator Operation 1. Turn the Sine Wave Generator on (if it is already on, turn it off for a second, then back on). The initial output frequency is 100 Hz. 2. Press the Up Increment key. The frequency changes to 200 Hz. Press it again and it changes to 300 Hz.
Page 7 Model No. WA-9867 Operation Duration of Each Note While in Auto Play mode, you can use the Frequency knobs to change the duration of each note. By default, each note is played for 1.5 seconds. If you turn the Course (1.0) knob one click clockwise, it will increase the duration by 1 second.
Page 8 Sine Wave Generator Operation Record a Sequence of Notes In Record Mode the display will always flicker. When you enter Record Mode, the display shows the output frequency. Connect the apparatus (such as a string vibrator with a string) to the Sine Wave Generator so that you can tune the frequency and amplitude for each harmonic.
Page 9: Specifications
Model No. WA-9867 Specifications Sequence Start-over: When the last stored note has been played, the Sine Wave Generator wraps around and starts over with the first note. At any time during play mode, a quick press of the Up arrow key will cause the sequence to start over with the first note.
Page 10: Operational Flow Chart
Sine Wave Generator Operational Flow Chart Operational Flow Chart ®...
Page 11: Applications
Model No. WA-9867 Applications Applications Open Resonance Tube The resonance tube shown here has both ends open and a fundamental resonance frequency of 120 Hz. It is set up to be driven by a speaker and Sine Wave Generator. (Note the position and angle of the speaker relative to the end of the tube.)
Page 12 Sine Wave Generator Applications 3. Press and hold the Play key to start Auto Play. The speaker will play 120 Hz, 240 Hz, etc., up to 720 Hz, then repeat. 4. You will notice that the tube does not resonate well above a certain frequency. When the sequence reaches the highest note that you want, press and hold the Play key.
Page 13 This automated display of a vibrating string is a good example of where the Advanced Mode is useful. With a 2 meter elastic cord and the PASCO String Vibrator (WA-9857), you can easily get a standing wave of 10 segments or more.
Page 14 Sine Wave Generator Applications ®...
Page 15: Experiment 1
Model No. WA-9867 Sine Wave Generator Experiment 1: Standing Waves In Strings Equipment Part Number Sine Wave Generator WA-9867 String Vibrator WA-9857 Braided String (inelastic, low-density) SE-8050 or similar Yellow Braided Cord (inelastic, higher-density) ME-9409 or similar Elastic Cord Part of WA-9857, SE-9409 or similar Banana Patch Cords (qty.
Page 16 Sine Wave Generator Standing Waves In Strings A stretched string has many natural modes of vibration (three examples are shown above). If the string is fixed at both ends then there must be a node at each end. It may vibrate as a single segment, in which case the length (L) of the string is equal to 1/2 the wavelength (λ) of the wave.
Page 17 Model No. WA-9867 Experiment 1: Standing Waves In Strings Setup 1. As shown in the picture, clamp the Sine Wave Generator and pulley about 120 cm apart. Attach about 1.5 m of braided string to the vibrating blade, run it over the pulley, and hang about 150 g of mass from it.
Page 18 Sine Wave Generator Standing Waves In Strings using a strobe light if one is available. Adjust the strobe frequency to be near the frequency of the Sine Wave Generator. The string will look like it is moving in slow motion. 6.
Page 19 Model No. WA-9867 Experiment 1: Standing Waves In Strings Part II: Wave Speed and String Density Theory As stated in Equation 1, the speed of any wave is related to the wavelength and the frequency. For a wave on a string, the speed is also related to the Tension (F) in the string, and the linear density (µ) of the string, as shown by...
Page 20 Sine Wave Generator Standing Waves In Strings Procedure 1. Clamp the String Vibrator about 120 cm from the pulley. Hang about 50 g from the string over the pulley. Measure from the knot at the vibrating blade to the top of the pulley. This is the distance L.
Page 21: Experiment 2: Resonance Tubes
Model No. WA-9867 Sine Wave Generator Experiment 2: Resonance Tubes Equipment Part Number Sine Wave Generator WA-9867 Open Speaker WA-9900 or similar Banana Patch Cords (qty. 2) SE-7123 or similar Economy Resonance Tube WA-9495 Twirlable Sound Tubes (optional) SE-8692 (4-pack)
Page 22 Sine Wave Generator Resonance Tubes Part I: Closed Tube of Variable Length Theory A resonating tube with one end open and the other end closed will always have a node at the closed end and an anti-node at the open end. A node represents an area where the velocity of the air is a minimum (zero), and an anti-node represents an area where the velocity of the air is a maximum.
Page 23 Model No. WA-9867 Experiment 2: Resonance Tubes 2. Extend the tube to 120 cm. Set the Sine Wave Generator frequency to 50 Hz, and turn up the amplitude to a reasonable level. 3. Slowly increase the frequency using the coarse (1.0) knob, and listen for resonance. When you are within a few hertz of the fundamental frequency, the loudness off the sound will increase noticeably.
Page 24 Sine Wave Generator Resonance Tubes Further Investigations 1. Set the frequency to 230 Hz, and extent the tube to 120 cm. Without changing the frequency, slowly shorten the tube until you hear resonance. Adjust the tube length back and forth across the resonance to locate the position of the node.
Page 25 Model No. WA-9867 Experiment 2: Resonance Tubes 2. Set up the Sine Wave Generator and the speaker as before. Start with the frequency at 50 Hz and slowly increase it using the coarse (1.0) knob. Find the frequency of the fundamental (to the nearest 1 Hz) as you did before.
Page 26 Sine Wave Generator Resonance Tubes ®...
Page 27: Experiment 1
Model No. WA-9867 Sine Wave Generator Experiment 1: Teachers’ Notes–Standing Waves in Strings String Slope = 97900 Hz 4 9.8 m/s   4 – µ ×  --------------------------------------------------------------- - Density 2.65 kg/m 0.265 g/m 97900 Hz 1.23 m ...
Page 28 Sine Wave Generator Teachers’ Notes–Standing Waves in Strings Elastic Cord Minimum Slope = 5890 Hz 4 9.8 m/s   3 – µ ×  ------------------------------------------------------------ - Density kg/m 4.4 g/m 5890 Hz 1.23 m    5.58 g Actual Density (unstretched) ----------------- - 4.3 g/m...
Page 29: Experiment 2
Model No. WA-9867 Experiment 2: Teachers’ Notes–Resonance Tubes Experiment 2: Teachers’ Notes–Resonance Tubes If you have twirlable Sound Tubes (SE-8692), trim them to slightly different lengths so they play different notes. Part I 1/ f (cm) (Hz) (1/Hz) 0.015 0.014 0.013...
Page 30 Sine Wave Generator Teachers’ Notes–Resonance Tubes 1st Harmonic 3rd Harmonic Part II = 122 Hz (fundamental) λ = (346 m/s)/(122 Hz) = 2.84 m L = 1/2 λ = 1.42 m (effective length) Actual Tube Length = 1.31 m End effect (per end) = (1.42 m-1.31 m)/2 = 5.5 cm, which is between the values from Part I. 3rd Harmonic ®...
Page 31: Safety
Wave Generator Instruction Manual is Technical Support copyrighted and all rights reserved. However, permission is granted to non-profit For assistance with any PASCO product, educational institutions for reproduction of contact PASCO at: any part of this manual, providing the reproductions are used only for their Address: PASCO scientific laboratories and are not sold for profit.