Just for fun, but a curious observation…
Analogs vary continuously; Digitals step.
Analog watches tick; digital watches don’t.
(By the way, the internet is a wonderful source of knowledge but the things we find are not always correct. If we do a search on watches ticking we might find a reference to Rolex. Some of the information about Rolex watches is incorrect and a look at the official Rolex site will correct those errors.)
The question might then arise; what’s the difference between an analog and digital watch? The answer might very well be…it depends on how we watch it.
Let’s say a digital watch has a timing mechanism which is timed by a piece of quartz. The manufacture sizes the quartz to vibrate at 32768 Hz. That frequency is then divided down to a 1 second pulse and the pulse is then used to display digits. People would regard that as a digital watch.
Now let’s say the same 1 second pulse was used to drive a stepper motor which moved hands over a dial. People would regard that as an analog watch.
So, in this case, both watches have the same digital timing mechanism and both watches step their display of time. Both watches are digital, but one is regarded as digital and the other is regarded as analog.
A mechanical watch is no different. A mechanical watch is timed by a swinging mass driven by a spring, similar to a pendulum driven by gravity. The swing causes an escapement mechanism to release energy on a regular bases. The regular base is a pulse to drive the display of the watch, the hands over a dial.
I both cases the, electronic watch and mechanical watch, step the display due to a pulse. The pulse has a discrete value and hence it is digital. Both watches are digital but one would be regarded as analog and the other regarded as digital.
The difference between analog and digital here is how the user perceives the difference. They are both digital because they are both operating from discrete values.
Let’s have a look at Voltage…
A Voltage exists in an electrical circuit.
An electrical circuit has capacitance, so let’s give it some, 1 Farad.
The Voltage on a capacitor changes with electrical charge, so let’s give it some, 1 Coulomb.
A Coulomb is 1 Ampere per second.
An amp per second is approx. 6x10^18 electrons.
The electron is regarded as indivisible.
So, the transfer of 1 Coulomb of charge to/from a 1 Farad capacitor changes the Voltage on that capacitor by 1 Volt. That 1 Volt is made up of ~6x10^18 steps. The steps are discrete values because the electron is indivisible.
Discrete values of electrons make the Voltage in an electrical circuit digital.
We can change the size of the capacitor, we can change the Coulombs transferred but we can not change the charge on an indivisible electron. The Voltage remains a discrete value, the Voltage remains digital.
The word analog appears to be a decision by the perceiver to ignore the detail and make the assumption that things can change with infinite resolution. It is a practical assumption with some merit, but it is not real.
At the large scale it may remain a practical assumption but as electrical circuits become smaller it won’t. By now we may be talking about capacitors with 1x10^-15 Farads (Do the math; we could measure the Voltage step change.) I don’t know, but things are getting smaller. As things get smaller the ingress of 1 electron may become significant.
The internet is a wonderful source of knowledge but the things we find are not always correct. In this instance, I needed Rolex for the tick.
Chris.
or not whatever............
yep they are not techincally drives but a disk and a drive can be viewed as different devices.
