This is an automated archive made by the Lemmit Bot.

The original was posted on /r/explainlikeimfive by /u/Fiempre_sin_tabla on 2023-06-27 00:36:28+00:00.

Some electronic (not talking about old-old purely mechanical) control dials are “clicky” – there’s probably a better word for it; I don’t just mean that there is a click-stop/detent effect to turning the knob, I mean each click always gives a specific increment of control. Example: on a washing machine, if there are (say) twelve different cycle options, each one has its own certain detent, and when you reach that detent, you get that cycle. It doesn’t matter if you reach that detent by turning the knob slowly or fast; if you want whatever the seventh cycle around the dial is, you just have to glance at the dial and see where it is, then you can select your chosen cycle without looking: if the dial started all the way counterclockwise, you rotate it (fast or slow) through six click-stops. If the dial started two cycles to the left of your chosen one, you rotate it (slow or fast) through two click-stops. And you arrive at your chosen cycle every time.

Or on a dryer, if there is a dial to choose a time between 10 and 90 minutes, passing through each detent adds or takes away a certain specific number of minutes on the display, no matter how slowly or fast you pass through the detents.

Same on an oven with a dial to set a temperature between 95 and 290 °C; passing through a single detent adds or takes away a specific number of degrees (usually 5 or 10)…again, no matter if you slowly and deliberately cross each detent, or grab the knob and gave it a zesty spin.

With other control knobs that’s not the case, they’re more “stretchy” (again, probably not the right word). The volume and tuning knobs on my last two car radios from 2008 and 2016 have been “stretchy”, and same with two different washers, one from 2003 and one from 2020, and also a dryer from 2020: if you very slowly turn the knob you get one increment per detent, but if you spin it faster it sort of slips: you can hear/feel you went through a bunch of detents, but you only jump one cycle, or only add or take away a small number of dryer-minutes or a small amount of radio-volume. If you keep grabbing and spinning, you can eventually get to what you want, but you’ll rack up a big total of detents crossed.

Or, the opposite: if you turn the knob very slowly, either it doesn’t change the setting or it only bumps the setting by one increment after you’ve (slowly) gone through a whole bunch of detents, but if you grab the knob and give it a sharp crank, the setting goes to whichever end of the range you turned towards, even if you just crossed relatively few deteents.

What makes the difference in how these kinds of controls operate? Are they different kinds of devices behind the control knob? Different programming of the circuitry? Something else?