Hall sensor confusion

[goatman]

ok, that makes sense.
sidenote
I was going to use a led but a led has no real resistance, I hooked 1s2p directly to 3 leds and it was almost like a welding flash. kind of like 20 amps was being pumped into them, they didn't blow and I put a resistor inline so I could use the led normally

that's why I asked about 12v automotive not led, I didn't want to pull 10 amps through the hall sensor

 

[amberwolf]

I was going to use a led but a led has no real resistance, I hooked 1s2p directly to 3 leds and it was almost like a welding flash. kind of like 20 amps was being pumped into them,

an led (just a bare led, no driver) is a current-operated device, not voltage. it does have a minimum voltage requirement, but actually is operated by current.

so to use one, you need to know what current it was designed to take. then you need to know what voltage you're running it on. then you use ohms law to figure out what resistance it takes at that voltage to get that current, *at maximum*.

you don't want to exceed taht current, because it greatly shortens the led life (if it doesn't blow it up outright), and decreases it's max brigthness, permanently.



incandescent bulbs are voltage-operated devices, and self-limit their current draw when used at their rated voltage, to what is needed to operate as designed.

exceed the voltage, and it's just like leds--shortened lifespan. (their max brightness isn't reduced, but they are much easier to burn out at the hgiher voltage from even small vibrations, the moreso the higher the overvoltage).

 

[dogman dan]

Well, theres the problem, I am a dummy who can't even understand half what AW says. And then I explain it for dummies, but poorly since I am a dummy.

Yes, Dmm goes on the red, and the green or blue or yellow. I thought he meant he put the battery + on the g y or b.

Battery goes on the halls red and black.

 

[TommyCat]

Perhaps a couple of graphics to clarify...

 

[MadRhino]

I do this exactly, with a 9v battery and 3 12v LED. It worked with all motors that I have tested, so we can presume that all hall sensors can take 9v no problem. Also, I had one of those small Chinese ebike testers, that was powered with a 9v battery as well, although I never checked if it was 9v output on the test wires.

 

[amberwolf]

many of these motor hall sensors can take up to 24v (some even more) for their +power pin to ground pin. you can look at the spec sheet for the sensor you're testing to know for sure.

there are some that are 5v *only*, and 9v will damage them. but they are not the ones commonly used in ebike motors.

the most common type:

https://sensing.honeywell.com/ss411a-bipolar2

"3.8 Vdc to 30 Vdc supply voltage" though there is a note "For supply voltages above 24 Vdc, a capacitor may be needed between the output and supply pins to ensure proper operation."


fwiw, the actual honeywell-made sensors can operate up to 302F temperatures...who knows what the generic chinese clones can take. might be important for those pushing enough power thru the motors to make them toasty.

 

[docw009]

I do this exactly, with a 9v battery and 3 12v LED. It worked with all motors that I have tested, so we can presume that all hall sensors can take 9v no problem. Also, I had one of those small Chinese ebike testers, that was powered with a 9v battery as well, although I never checked if it was 9v output on the test wires.

On my little tester box, the Hall connector has 5.0 volts across red/black.