Recent content by tech99

Regarding the spacing of resonance as you vary the wavelength (or frequency). Imagine a low frequency analogy. Take transmission line 5m long with a short circuits at each end. Apply some energy at frequency that can be varied from zero upwards. When the wavelength becomes 10m, corresponding to...

If you change wavelength, the resonances actually occur at fixed intervals of frequency, so are not exactly uniform wavelength intervals.

Isolated systems are used for safety on construction sites etc. A transformer is used where the secondary is not connected to earth. A problem arises, however, if the system gets very big and an accidental connection to earth occurs on one wire. Then the system is dangerous, because if someone...

I was assuming that the supports were knife edges so that the structure could lift off.

My ideas are as follows:- If we are to ignore weights, the structure cannot be in equilibrium. So we must assign a weight W to the total structure and we have a centre of mass located on the vertical centre line. The structure acts exactly the same a a block of wood; you do not need to analyse...

Is the spectrum analyser set to a very narrow bandwidth so that the problem is exaggerated? You seem to obtain a bandwidth of just a few Hertz. Could the cavity be subject to acoustic or mechanical vibration?

An example of a device where positive and negative charges flow in opposite directions is the demountable discharge tube made by Teltron, https://www.healthandcare.co.uk/student-tubes/teltron-discharge-tube-s.html. This has a screen at each end, one showing the negative beam and the other the...

I think the basis of the first understanding the proton was the cathode ray tube of Eugene Goldstein in 1886. In essence, the tube was a simple mass spectrometer, also used by J J Thompson to study the electron. I understand that the Penning trap was not made to work until 1959.

For the case of a standing wave, there is no net flow of energy - the energy is stored. The electric and magnetic fields are no longer in phase, but in quadrature, and the nodes and antinodes for electric and magnetic fields are physically displaced from each other by a quarter of a wavelength.

I think what is being described is a zone plate.

Is not the shape of the field simply the superposition at every point of radial fields from more than one body? This gives the curvature.

There is an excellent book called Tuning for Speed by Phil Irving.

I think the view is that small events occurred and there was insufficient stored energy in the system to cope with it, so more rotating machinery (or electronic equivalent ) will be required.

I think my own method here is to work with an electrical analogy. (Of course, it is only my familiarity with electricity which makes me do that, because the equations are equivalent). An analogue of compliance is capacitance. So you can draw a network of six capacitors having values equal to the...

Wind will exert a force even on a static object, due to the change in momentum of the air particles, so no flow past the door is necessary. I remember from the days when we used Imperial units that the pressure exerted by a 10 mph wind on a flat surface was approx 0.4 pounds per square foot. It...