Regulator, is limited to that available to the members of the species
Homo? Does this imply that no advance in regulation is possible
(for the regulator will have to be built by members of the species)?
It does not; for when regulation is achieved in stages— when a
Regulator R1 acts so as to bring into existence a regulator R2—the
Capacity of R2 is not bounded by that of R1. The possibility arises
263
A N I N T R O D UC T I O N T O C Y B E R NE T I C S
That R2 may be of capacity greater than R1, so that an amplification
Occurs. This possibility is studied in the next chapter, where we
Shall see that, apart from being necessarily wasteful, the method
Of regulation by stages opens up some remarkable possibilities.
264
Chapter
14
A MPL IFYI NG R E GUL AT ION
What is an amplifier? An amplifier, in general, is a device
That, if given a little of something, will emit a lot of it. A sound
Amplifier, if given a little sound (into a microphone) will emit a
Lot of sound. A power-amplifier, such as the one described in
S.12/21, if given a little power (enough to move L) will emit a lot
Of power (from H). And a money-amplifier would be a device
That, if given a little money, would emit a lot.
Such devices work by having available a generous reservoir of
What is to be emitted, and then using the input to act as controller
To the flow from the reservoir. Rarely an amplifier acts by directly
Magnifying the input, as does the cine-projectionist’s lens; but
More commonly it works by supplementation. Thus the
Power-amplifier has some source that will provide power abun-
Dantly (the compressed air at A in Fig. 12/21/1), and it is this
Source that provides most of the power in the output, the input
Contributing little or nothing towards the output. Similarly, the
Work performed by the cranedriver on the control-handle does
Nothing directly towards lifting the main weight, for the whole of
His work is expended in moving electrical or other switch gear.
It will be seen that in the power amplifier (e.g. that of Fig. 12/21/
The whole process— that of lifting a heavy weight at H, by a
Force at L— goes in two stages, by two coupled systems. It is this
|
|
|
Separation into two stages that makes power-amplification possi-
Ble, for otherwise, i.e. in one stage, the law of conservation of
Energy would make any simple and direct amplification of power
Impossible. Stage 1 consists of the movement, by the operator, of
The point L against the friction at K and the pressure at V; over this
Stage energy, or power, is conserved strictly. Stage 2 consists of the
Movement of compressed air into or out of B and the lifting of P,
G and H; over this stage, also, energy is conserved; for the energy
Used when the weight at H is lifted is derived from the expansion
Of the compressed air. Thus the whole system can be regarded as
Composed of two systems, within each of which energy is con-
served strictly, and so coupled that forces of 0, 1, 2…dynes at L
correspond respectively to forces of 0, 1000, 2000,… dynes (or
265
A N I N T R O D UC T I O N T O C Y B E R NE T I C S
A MPLI FY IN G R EG U LA TI ON
Some other multiple) at H. It is the division into two stages that
Enables a power-amplifier to be built in spite of the law of conser-
Vation of energy, the point being that the energy supplied to the
Input in stage 1 can be supplemented to give the output in stage 2.
Sometimes the proportionality is important, as in the radio
Amplifier. Then the machine has to be made so that the ratio has
The same value all along the scale. In other cases the exact value
Of the ratio is of little importance, as in the crane, the essential
Point in it being that the input values shall all be within some
Given limit (that set by the strength of the crane driver’s arm) and
Дата добавления: 2019-11-16; просмотров: 238; Мы поможем в написании вашей работы! |
Мы поможем в написании ваших работ!