- #1
freddyfish
- 57
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Hey
I wounder why an approaching electrical impulse is completely reflected if you short-circuit the conductor. I have read some explanations suggesting it is because Kirchhoffs law must be satisfied, but that argument falls badly when the conductor is long and the pulse short, such that there will be no constructive interference and doubling of amplitude. According to the formula zc=(z1-z2)/(z1+z2) there should be no reflection, since the characteristic impedance of the two parts of the conductor have the same characteristics.
If the above z1 instead is the impedance/resistance (instead of the characteristic impedance) of the first part of the conductor, this would mean that a resistor inserted between the two conductors that earlier composed the short-circuit would cause reflections even though its impedance matches the characteristic impedance of the conductor.
Thanks
I wounder why an approaching electrical impulse is completely reflected if you short-circuit the conductor. I have read some explanations suggesting it is because Kirchhoffs law must be satisfied, but that argument falls badly when the conductor is long and the pulse short, such that there will be no constructive interference and doubling of amplitude. According to the formula zc=(z1-z2)/(z1+z2) there should be no reflection, since the characteristic impedance of the two parts of the conductor have the same characteristics.
If the above z1 instead is the impedance/resistance (instead of the characteristic impedance) of the first part of the conductor, this would mean that a resistor inserted between the two conductors that earlier composed the short-circuit would cause reflections even though its impedance matches the characteristic impedance of the conductor.
Thanks