So in my life I have been playing with electronics and water for a very long time. I thought I had a pretty good grasp on both, but I am a bit perplexed.....I ordered a couple of these:
http://www.ebay.com/itm/Pool-Liquid...716?pt=LH_DefaultDomain_0&hash=item4176478874
some time ago. I ASS-U-MEd these were simple magnetic reed switches when I ordered them....silly me. The specs are as follows:
Obviously something is lost in translation, the "minimum voltage: 250V DC" must be "minimum isolation voltage" or something similar. The switches work just fine @ 5V driving an LED; however they do not work at all if tested with a multimeter, implying they have some minimum voltage/current requirements. They work independent of polarity and appear to have a very low "on impedance".
So, they work just fine, but the inquiring mind wants to know why/how. I ASS-U-ME they are some type of hall effect device, and that the float has a small magnet in it. They are DIRT CHEAP, so the technology//part count is likely quite low. Here's the thing though, I can think of dozens of applications where bi-directional DC switching of 5-100Vdc @ 500mA activated by a magnetic field would be really cool! But I can't think of a way of doing it for < $2 per switch, LOL. So.....how'd they do that?
Fish
http://www.ebay.com/itm/Pool-Liquid...716?pt=LH_DefaultDomain_0&hash=item4176478874
some time ago. I ASS-U-MEd these were simple magnetic reed switches when I ordered them....silly me. The specs are as follows:
Code:
Specification:
Cable length: 30.5cm
Maximum load: 50W
Max switching voltage: 100V DC
Minimum voltage: 250V DC
Maximum switching current: 0.5A
Max load current: 1.0A
Temperature rating: -20°C - +80°CObviously something is lost in translation, the "minimum voltage: 250V DC" must be "minimum isolation voltage" or something similar. The switches work just fine @ 5V driving an LED; however they do not work at all if tested with a multimeter, implying they have some minimum voltage/current requirements. They work independent of polarity and appear to have a very low "on impedance".
So, they work just fine, but the inquiring mind wants to know why/how. I ASS-U-ME they are some type of hall effect device, and that the float has a small magnet in it. They are DIRT CHEAP, so the technology//part count is likely quite low. Here's the thing though, I can think of dozens of applications where bi-directional DC switching of 5-100Vdc @ 500mA activated by a magnetic field would be really cool! But I can't think of a way of doing it for < $2 per switch, LOL. So.....how'd they do that?
Fish
