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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See the red line in this photo. Retrieved March 23, Could be wrong, but I believe the wood right next to it will have a significant effect. Two methods are employed to find the nodes.

At the other end the rods are connected together with a conductive bar between them. What follows is a bit about Lecher lines, how I did it, and the results.

The separation between the Lecher bars does not affect the position of the standing waves on the line, but it does determine the characteristic impedancewhich can be important for matching the line to the source of the radio frequency energy for efficient power transfer. Propagation velocity depends on the dielectric. In precision wavemeters an RF voltmeter is used. How do you test the oscillator circuit you just made that runs between MHz and MHz if all you have is a MHz oscilloscope, a few multimeters and a DC power supply?


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. From Wikipedia, the free leche. R Jessop [15] uses a Lecher line anode tank.

Using a Lecher Line To Measure High Frequency | Hackaday

The Principles of Electric Wave Telegraphy. The shorting bar is slid down the line and the position of two successive current minima is noted, the distance between them is half a wavelength.

You are commenting using your WordPress. Notify wlre of new comments via email. The Electrical Engineer, Ltd. Wiree major attraction of Lecher lines was they were a way to measure frequency without complicated electronics, and could be improvised from simple materials found in a typical shop.

This reminds me of the fun part of physics classes. It would be great to see a visual explanation showing using a light particle model- showing how the light particles are absorbed and create the electric potential between both sides of the diode when the screwdriver is at a node. Short lengths of Lecher line are often used as high Q resonant circuitstermed leched stubs.

The end with the oscillator but pulled back from the Lecher line. Radar circuit analysis by United States. There is wooden base under wires.


Lecher line

Notify me of new posts via email. As a typical example, something like a Colpitts oscillator may be used, tuned with a varicap diode that changes its depletion capacitance strongly as the bias voltage across the diode changes — which is what allows control of the oscillator frequency from an applied bias voltage. The Speed of Light. More fun discovering Lecher Lines though. When attached to a source of radio-frequency power such as a radio transmitter, the radio waves form standing waves along their length.

An improved Lecher wire experiment – IOPscience

Enhanced version and more background: Part of that loop is a 6. By sliding a conductive bar that bridges the two wires along their length, the length of the waves can be physically measured. The one objection is: Apparently the screwdriver causes a reflection creating a standing wave of voltage and current on the line. 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.

One problem with using glow discharge bulbs is their high striking voltage makes it difficult to localize the exact voltage minimum.