I don't think it's a clicking sound, yours sounds more like jawbone as they sometimes click when swallowing. I have heard more of a thub,thub sound couple of times I had it when very stressed out taking care of my parents few yrs back, Haven't had it since they passed away. Usually have low BP . Is your BP high, I don't think it could be heart at all, just where the jaw hinges on both sides back by your ear, for awhile when they were trying to realign my jaw to get rid of migraine headaches drs were doing a surgery on the jawbones of people but about 10 yrs later it came out that they were mostly a mistake as the problems got worse.(but they made lots of money on the surgeries) Might be like some people can crack their knuckles & others can't just a family trait!

To clarify a bit, the technical term for the "duty cycle" is "Pulse Width Modulation." It is also the way most microwave ovens work. At any setting below full power, the heating power is switched on and off with the amount of "on" time and off "time" being averaged to approximate a selected level of heat. The boil-stop-boil-stop results from the use of low-frequency switching electronics in many portable induction cooktops (PICs) and some induction ranges and built-in cooktops. That is, the power is switched on for a second or two, then off for a few seconds, then back on for a second or two, then off for several more seconds. More sophisticated PICs and many built in cooktops and induction ranges avoid noticable pulsing with electronics that switch the burner power on and off many times each second. My personal experience with browning butter in a thick bottomed pan (cast iron) on an inexpensive PIC was rather mixed. This was some years ago and was tried with a ten-inch cast iron pan on some less expensive PICs (a Duxtop/Secura model and a Max Burton one). Basically, it was problemmatic when working with smaller quantities (say, half a stick of butter) and sort-of okay with two or three sticks provided I took a long time to preheat the CI pan. Might have been different if I'd had a smaller cast iron sauce pan, but I doubt it. Like metlmann, I just found it easier to use a burner on a gas stove for that task and moved on after several less than satisfying experiments with the inexpensive PICs. FWIW, I recently easily browned a small quantity of butter in an ordinary small saucepan on a Vollrath commercial PIC unit. The Vollrath does not seem to have the pulsing problem on anything I've used it for.

Ours are also ChoiceMMEd. We checked their performance against the hospital one when DH was hospitalized for so many months last year. The pulse ox was the one cord that ALWAYS seemed to get him tangled up and wrap around all the other thousands of cords and devices, so we ordered this one and I checked him with it every 30 minutes while he slept so he could take off the corded hospital provided one. The nurses were okay with me doing that because we demonstrated that the two displayed almost identical values, never more than 1 percentage point difference. They couldn’t enter our oxi meter results in his chart but if it ever dropped to 94% I put the corded one back on for continuous monitoring.

Joe -- the pulsing you are seeing is pretty much endemic to lower-priced portable induction cookers (PICs). The other name for what Kaseki called "duty cycle" is "pulse width modulation" (PWM). Microwave ovens use the same technique, switching power on and off at higher or lower frequency to simulate higher and lower power settings. The idea is that the heat averages out , although the average between the state of boiling and still water may not be the same as water at a more steady heat level. Having more power settings and/or settings targeted to temperature doesn't necessarily address the PWM frequency unless there is some kind of in-pan temperature probe. Induction units with in-pan probes are becoming available but still seem to be very expensive. PICs can be built with high-frequency switching where the on-off switching happens so many times per second --- as Weed describes --- that the pulsing is rarely perceptible even with thin pans. Trouble is, the high frequency switching components are comparatively expensive. Using heavier pans (like the LeCrueset you mentioned) will help somewhat on better quality PICs and hobs but, as you are seeing, does not solve the pulsing problem when using the less expensive PICs like the one you apparently have. If you were in the US, I would point you to the Century Life blogs site (link to their article on PICs). I don't know anything about the T-Fal you asked about but suspect that it is made either by Fagor or one of the Chinese factories to which many PIC brands sub-contract their production. Most, if not all of those, have the crude PWM electronics. The Century Life site recommends the Vollrath Mirage PICs for units that do not exhibit the boil-still-boil-still pattern. These are commercial units and, over here, the Vollrath units have been priced at about half-way between the lower-end PICS and what is usually charged here for the commercial-grade Cookteks that Kaseki and Weed have. Don't know if that will hold true in the UK but I believe that the Mirage units are available in the UK., at least from food service companies. You might try following up on that and seeing if searching on "Vollrath Mirage Induction" turns up some similar units from other brands which might be more favorably priced.