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K8-32. Pulses In Transmission Lines
Purpose
To demonstrate the reflection of pulses in terminated and unterminated transmission lines and to determine the speed of an electromagnetic wave in the transmission line.
Equipment
Oscillator, dual trace scope, 100 feet of 50 ohm cable, shorting and 50 ohm terminators.
Setup Time
5 minutes.
Images
Description
An oscillator produces pulses at a rate of about 8 Mhz, which are input into the transmission line. The scope is triggered externally and the pulse is displayed on the top trace of the dual trace scope. The pulse at the end of the transmission line is displayed on the bottom trace. For a short section of transmission line the input and output pulses line up. Using 100 feet of transmission line the delay is about 150 ns; for this cable v/c is approximately 0.67 so the wave time is about 1.5 nanosecond per foot.To see reflections, use only the top trace. The far end can be left open, shorted, o
References
H. P. Stabler, Apparatus Notes: Pulses on a Transmission Line with a Tektronix 545A
Oscilloscope, AJP 29 #2, ix-x (1961). Ronald I. Rank, Speed of a Pulse in a Transmission
Line, TPT 7, 344-345 (1969). ◙D. J. Martin, Wave propagation in dispersive and attenuation
media: A delay line simulation of plasma waves, AJP 48, 473-477◙(1980). Operating
Instructions, Short Wave Radio Demonstration Apparatus, Cenco No. 080435, Cenco Scientific
Co., Chicago, IL. Lecture Demonstration Photographs and description of Demonstration.
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See pagesk1. forces on moving charges
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See pagesk2. electromagnetic induction
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See pagesk3. transformers
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See pagesk4. motors & generators
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See pagesk5. electrical properties of matter
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See pagesk6. electric circuits & instruments
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See pagesk7. rlc circuits
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See pagesk8. electromagnetic waves
-
See pagesk1. forces on moving charges
-
See pagesk2. electromagnetic induction
-
See pagesk3. transformers
-
See pagesk4. motors & generators
-
See pagesk5. electrical properties of matter
-
See pagesk6. electric circuits & instruments
-
See pagesk7. rlc circuits
-
See pagesk8. electromagnetic waves