Why did we switch from CPS to Hz?
More importantly, why?
Cycles per second seems much more descriptive than Hertz.
Any particular reason or is this just scientific mumbo-jumbo?
And who was Hertz anyway? (No, don’t mention the truck rental company :))
Why use Hz instead of cycles-per-second? Why use amps instead of coulombs-per-second? Because it saves time. We define units of measurement for convenience. Everybody who needs to know what a Hertz is knows what it is. And it’s not too hard to find out if you don’t know.
My biggest beef is that it sounds plural, so I feel like a knob saying “1 Hz”.
Hertz allows for more effective use of puns in everyday conversation (example) which is an intrinsic moral good unto itself.
There are many examples of this. In the SI system, the fundamental units are the kilogram (for mass), the meter (for length), the second (for time,) and the Kelvin (for temperature). Units for everything else are combinations of these fundamental units, but we sometimes assign that new unit a name of convenience.
Force is mass times acceleration, kg*m/s[sup]2[/sup]. We call that one the newton, after Isaac Newton.
Work is force times distance, kg*m[sup]2[/sup]/s[sup]2[/sup]. We call that one the joule, after James Joule.
Power is work per unit time, kg*m[sup]2[/sup]/s[sup]3[/sup]. We call that one the watt, after James Watt.
Cycles per second referred to as hertz is just one more instance of this. CPS is indeed more descriptive, just as kg*m[sup]2[/sup]/s[sup]3[/sup] is arguably more descriptive than watt - but watt and hertz are easier to speak.
Extreme Nitpick: Amp should be capitalized, it is an abreviation of Ampere, for André-Marie Ampère.
To the OP: In the 1970’s with the push to metrication, there was a reformation in the electrical field. This was very easy in the electrical field, as it has forever been essentially metric only modest changes were required.
The full suite of “by three order of magnitude” prefixes got used, replacing the abortion that was micro-microFarads with picoFarads and nanoFarads saving some ink with extra zeros. I think they used to say mega-mega-cps instead of GHz as well, but a lot of the work at those frequencies was classified, so I haven’t actually seen that.
Cycles-per-second make perfect sense and is instantly understandable…IF you speak English. Naming all the units in honor of electrical pioneers allows markings to be correctly interpreted by many nationalities. I have some Russian components with Cyrillic markings that are a bit of a challenge in this regard.
ETA: I may be wrong on the capitalization thing.
Didn’t we start with Hz?
I thought his first name was Richard.
Just thought of another thing: cycles per second was cumbersome enough in speech that it was common to just say “cycles”. This would then lead to confusion when you were actually talking about cycles rather than frequency, and I have witnessed it throw off some old-timers when stating a switch was rated for 1-million cycles, for example…doesn’t mean you can use it at 1MHz, means you can turn a batch of them on and then off a million times before half of them die.
I think you are. The guy’s name is Hertz, the unit named after him is a hertz. The Wikipedia list of derived units (many of which are named after people) has them all in lower case.
An amp, or ampere is a common thing, detectable and usable by anybody, owned by nobody. That makes it a common noun which is NOT capitalized.
The price of having your name is immortalized in some scientific term is losing the capital.
I think it was Button, or Butt Hertz, for short.
Actually the ampere is the fundamental SI unit of electrical current, expressed as 6.241x10[sup]18[/sup] electrons passing the measurement point over a period of one second. The coulomb is a derived unit of charge, defined explicitly as the amount of electrical charge carried by a current of one amp over a period of one second.
The volt is also a derived unit that replaces joules per coulomb (J/C). The math all works out rather nicely:
power = volts * current
watts = joules/coulomb * coulomb/second
watts = joules/second
Here’s a complete listing of SI derived units (including those with special names like hertz, and those without) and SI base units.
This made me snicker. You can visualize the guy installing the switch at the AM broadcast feedline. Hey, under 1M cycles, right?
Between the newbies and the old timers, how does anything go right?
That’s a good one!!! 
Then why is a unit of magnetism named after one of The Three Stooges?
In vibration analysis, we often talk in power spectral density where the units are G[SUP]2[/SUP]/Hz and sweep rates in Hz/s. Having to talk in terms "m[SUP]2[/SUP]·s[SUP]-1[/SUP]·cycles[SUP]-1[/SUP] or cycles·s[SUP]-2[/SUP] is clunky and non-intuitive, especially when the signal is stochastic. Hz is very often not (periodic) cycles per second.
Stranger
Good point. Bandwidth would be clunky to express without ol hertz.
Are there more than five members of the Three Stooges and I forgot one? Let’s see, Moe, Larry, Curly, Curly Joe, and Shemp. Perhaps there was a stooge name Gauss, Tesla, Oersted, or Weber, but I don’t recall.
But wait, maybe an MRI machine has a magnetic field of 1.5 Shemp.
Of course, there is an electrical unit, which went the route of the micro-micro farad, called the mho. It was a unit of conductance, the reciprocal of resistance, measured in ohms. Get it?
1/ohm = mho
This has since been replaced by the siemens (not the plural of something else).
The Stooge you’re missing is Joe Besser. He was after Shemp and before Curly Joe.
The unit names are lowercase. Most often, the corresponding symbol is a capital letter (or the first letter is capitalized. For example hertz = Hz.