Lords of the Ring

[Sauron]

Electrical Analogue

The analysis of mechanical and acoustical circuits is
made very much easier by the application of analogues in
which mass is equivalent to inductance, compliance to
capacitance, and friction to resistance.
Using SI units,
direct conversion between acoustical, mechanical and
electrical elements can be performed.

The beauty of the analogue method of analysis is that
it is possible by using various transformation equations
to refer the acoustic and electrical parameters to the
mechanical side, or conversely, the mechanical and
acoustic parameters to the electrical side, etc. For the
purpose of this analysis the electrical and acoustical
parameters are referred to the mechanical side. The
diaphragm can be thought of as an acoustic/mechanical
transducer ? that is, a device for transforming acoustic
energy to mechanical energy, and vice versa. Under
these circumstances it will also act as an impedance
transformer, i.e., it will convert acoustic inertance into
mechanical mass and acoustic compliance into mechanical
compliance and acoustic resistance into mechanical
resistance.

The most important parameter affecting the performance
of a loudspeaker is ?cone flexure?. Because real
materials are not infinitely rigid and have mass, the
velocity of propagation through the material is finite.
The cone is driven at the apex and the impulse travels
outwards towards the periphery where it is reflected
back to the source. At particular frequencies when the
distance to the edge are odd quarter wavelengths, the
returning impulse will be 180? out of phase and tend to
cancel; conversely, when the distance is multiples of half
wavelengths they will augment ? under these conditions
the system can be considered as a transmission line, and
theoretically (and to some extent, practically) if the
outer annulus were made resistive and of the correct
value the line would be terminated and no reflections
would occur.
The conical diaphragm also has radial or ?bell? modes
of flexure. These are similar to the resonances in a bell
and occur when the circumference is an integral number
of wavelengths.

[Sauron]

What is a valve?

Thermionic emission
Before transistors became common, all electronics relied
on the valve, there were even computers using valves!
All metals have free electrons within their crystal
structure, so some of them must be at the surface of the
metal, but they are bound there by the nuclear forces
between them and the adjacent atoms. However, the
atoms and electrons are constantly vibrating due to thermal
energy, and if the metal is heated sufficiently, some
electrons may gain sufficient kinetic energy to overcome
the attractive forces of the atoms and escape.

As a consequence of these escaping electrons, an electron
?cloud?, or space charge, forms above the surface of
the heated metal cathode. Once this cloud reaches a certain
size, it will prevent other electrons attempting to
escape from the surface because like charges repel, and
an equilibrium is therefore reached.
Some metals have stronger forces binding their electrons
than others, so stripping an electron from their surface
requires more energy, and the cathode has to be
heated to a higher temperature:

Melting point of pure tungsten: 3410?C
Pure tungsten cathode (transmitter valves and lightbulbs): 2700?C
Thoriated tungsten cathode (small transmitter valves): 1700?C
Oxide coated cathode (receiving valves): 1000?C

As can be seen, the operating temperature is sufficiently
high that the cathode could literally burn, so the structure
of the valve is enclosed in glass and the air is evacuated.
We now introduce a positively charged plate, or anode,
into the enclosure. Electrons will be attracted from the
cloud, and will be accelerated through the vacuum to be
captured by the charged anode, and thus a current flows.
The cloud has now been depleted, and no longer repels
electrons quite so strongly, so more electrons escape from
the surface of the cathode to replenish it. Current flow is
unidirectional because only the positively charged anode
is able to attract electrons, and only the cathode can emit
electrons. We now have a rectifier, but it requires rather
more than 0.7 V to switch it on; typically 50 V is needed.
In order to control current flow, we interpose a grid or
mesh of wires between cathode and anode, resulting in a
structure with three electrodes known as a triode.

If the grid is negatively charged, then it will repel electrons,
and although there is a space charge above the cathode,
no electrons reach the positively charged anode
because they are unable to overcome the repulsion of the
grid. The grid to cathode voltage Vgk therefore controls
the number of electrons reaching the anode, or anode current
Ia.

Mains borne interference is not a thing to be taken lightly.
Spikes of 1 kv and above are a common (in some areas frequent)
occurrence and this can and does damage unprotected equipment.

In addition to all man-made interference, there is another source
which will always be beyond any kind of legal
regulation and control ? the weather.
Electric storms and even lightning strikes make their presence
felt through the mains.

[tosky]

Hello Starcruiser,
The CTGLabs TPU looks like the S.M. TPU. How do you know it is not functional?

[joe dirt]

 

[Sauron]

i was talking about an EEG and the frequency's in the human mind......
but i like the degausing explenation.