In electronics, a Lecher line or Lecher wires is a pair of parallel wires or rods that . Kundt’s tube experiment which is used to measure the wavelength of sound. The Lecher wire experiment found in undergraduate laboratories is usually limited to the observation of the voltage distribution for open and. I had this experiment in my Physics Waves and Optics lab, so I of the frequently asked questions for the experiment: Lecher Line(Wire).

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The waves reflected from the short-circuited end interfere with the outgoing waves, creating a sinusoidal standing wave of voltage and current on the line.

The tuning necessary to select different stations is done by varactor diodes across the Lecher line. Then the distance from the end of the link to the shorting bar is a half-wavelength. Apparently the screwdriver causes a reflection creating a standing wave of voltage and current on the line. What follows is a bit about Lecher lines, how I did it, and the results.

You might have to remove paint from part of it the backside? Or if you rather use technology from 2 centuries ago, use that I suppose.

An improved Lecher wire experiment

Something else is still up…. Thanks for suggesting that. So the line presents an impedance to the applied power which varies with its length; when a current node is located at the entrance to the line, the current drawn from the source, measured by the ammeter, will be minimum.

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Looking at the chart, the error due to that is much smaller. The oscillator puts electromagnetic waves on the Lecher line using induction. The other method used to find the nodes aire to slide the terminating shorting bar up and down the line, and measure the current flowing into the line with an RF ammeter in the feeder line.

R Jessop [15] uses a Lecher line anode tank. As I slide the bar along the wires, it influences the waves. Leave a Reply Cancel reply Enter your comment here Radar circuit analysis by United States. Looking for more high frequency measuring projects here on Hackaday?

How does it differ from the POS? Dictionary of Pure and Applied Physics.

How does it work — does anybody know? An advanced treatise on alternating-current theory. That setup really helps de-mystify its mechanical equivalent at sonic frequencies, the transmission line speaker, and the currently popular mathematical model for it as described by Martin J. The next one further away is a full wavelength. For two parallel cylindrical conductors of diameter d and spacing D. You only do that if you want correct results.

From Wikipedia, the free encyclopedia. One difference between them is that transmission line stubs like Lecher lines also resonate at odd-number multiples of their fundamental resonant frequency, while lumped LC circuits just have one resonant frequency. But if I HAD to….

Using a Lecher Line To Measure High Frequency

The wikipedia article has a good description of this phenomenon. Short lengths of Lecher line are often used as high Q resonant circuitstermed resonant stubs.


Email required Address never made public. Thank you for this. They were also used as componentsoften called ” resonant stubs “, in UHF and microwave radio equipment such as transmittersradar sets, and television sets wure, serving as tank circuits expeirment, filtersand impedance-matching devices.

An improved Lecher wire experiment – IOPscience

When the screwdriver is still less than half a meter from the oscillator end, and at the node for the first half-wavelength, the voltage across the diode lfcher above 0.

Retrieved March 23, Notify me of new posts via email. This short circuiting termination reflects the waves. Less than half baked idea, but could a similar setup be used to detect the swinging length of a guitar string? Could be wrong, but I believe the wood right next to it will have a significant effect. To really make this article shine, it would have been nice to go back and verify the measurements with some known expwriment.

The uniform spacing of the wires makes them a transmission lineconducting radio waves at a constant speed very close to the speed of light. I measured the frequency by spanning three of them and then multiplying by three.

Experimenr wonder how easy it would be to use a fluorescent tube and measure of light intensity. The Principles of Electric Wave Telegraphy. The oscillator is a voltage controlled oscillator.