New Airwick aroma mist unit

That's roughly what I'd have guessed for the capacitors. 50kHz is higher than expected, but easy with a microcontroller. I wonder if the current sensing is just a precaution besides a fixed pulse length.

Big Clive

C9 (the one to ground) is 1nF and C8 is 100nF. L2 is 200uH, Q1 is G01N20 (200V, 2A, Nchan), Q2 is A1SHB. Seems to be about 50kHz and 50V with a 50% gate duty cycle .. so not sure what that sense resistor is doing, it doesn't seem to end the current pulse. I can't investigate further at present as I broke a leg off Q1 by poking it too hard.

adrian

I recall these, think they had aerial knobs that did it too for the old Amps phones! The amps and GSM phones were capable of much more transmit power than modern ones need. often watts, or at least a good part of a watt! now days, ironicly, the 5G and 4g, in fact, all the CDMA based technologies are vastly lower power, so they probably just won't make enough voltage to fire up the LEDS. It's funny how the nutters are so much more upset about the modern tech considdering the vastly lower power levels!

William Taylor

I get that you might want some extra capacitance for tuning, but why two? It would be interesting to know their values. I'm expecting something in the 1-100nF range.

Mike Page

Yeah, the capacitors have me puzzled. I'm guessing the series one is quite high value, and the parallel one is low value for spike clipping?

Big Clive

I think it's just the easiest way to get atomisation with low power. If mounted sideways it would probably leak like a Duracell. Many of the USB humidifiers on eBay use the wick approach.

Big Clive

Yeah, it took a moment to open it.

Big Clive

I think you're right, Clive: the bootstrapped supply must be so the batteries can be squeezed dry towards the end of life. This also explains why there are two boost stages. They must have had an important battery life spec to hit. MCUs go down to 1.8V, though sometimes analogue performance is not guaranteed. But also possible they couldn't find an output FET which could drive the inductor at low Vgs without self-destructing. The capacitive divider around the piezo has me bamboozled. Seems really wasteful.

Mike Page

If batteries weren't a priority for the industrial designer, you get the space you're given ;)

Mike Page

Curious that it takes 3 batteries. Is there not a convention on using an even number?

Rasmus

I think RB is Reckitt & Benckiser, according to https://www.reckitt.com/about-us/who-we-are/ They carry the Air Wick brand, among many others. Confirmed by https://www.whois.com/whois/rb.com; Reckitt Benckiser Corporate Services Limited

Paul Schuur

Also neat is the liquid wicking into the piezo, i have not seen that before. It means as in your video that it works sideways as normal piezo vapour devices need a covering of liquid.

Tokkan FX

Maltesers as in Androids candy version names.... 🤣

Last week I opened one of mine.... 🤣

I got one of these a couple of months back, the first bottle was me proof as well, initially at least!

Dr Andy Hill

Bizzare !

Simon Midgley

Yeah, I was pondering that afterwards.

Big Clive

Did it really say 'Maltesers' on the circuit board in reverse !! Good Video as allways 👍

Simon Midgley