I was looking for a replacement component for what I thought would be a "Hall effect sensor" (used in an electric scooter throttle handlebar). I had bought a replacement throttle about a month ago, but now it's dead again so I dismantled one of them and figured I'd just replace the sensor this time.

Here's a scanned image of the sensor (the white is some glue they used to keep it in place):

Scanned image of the sensor

A search on S49EH got me to the site of the Chinese manufacturer, who claim it is a "Holzer element". Wikipedia has no mention of "Holzer" on the Hall effect page, however another source seems to describe the same effect calling it the Holzer effect. Is it really the same or is there a slight difference I missed?

I'm still at a loss to find a correct replacement though. A search at my local electronics dealer on "nonlineair hall-effect sensor" gave zero results. they do have linear, digital, switching and others. After looking at a lineair version, it seems to be outputting 50% of the voltage when detecting no magnetic field, which is not desired. The output should be between the input (5VDC) and 0.

Doing some experimenting, it seems that using a potentiometer of 10K also has the desired effect (only mounting it on the throttle in a safe way would be quite a challenge).

Also (maybe this should be a separate question), what can I do to prevent the new sensor from breaking once again? According to the specs the old sensor should be able to handle 24Volts, while I'm only measuring 5 volts on my scooters throttle. Placing a serial resistor would decrease my maximum speed so that's not an option. Maybe putting a small capacitor between the input and GND would buffer some voltage peaks?

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    \$\begingroup\$ Notice that only certain Chinese sites refer to the Holzer effect, and only Chinese manufacturers offer Holzer Effect parts. Also, the "Anomalous Hall Effect" and the "Anomalous Holzer Effect" sound suspiciously similar. It is almost certainly a local "urban legend" in China that "Holzer" existed at all. :-) \$\endgroup\$ Commented Sep 1, 2013 at 8:11
  • \$\begingroup\$ First I'd check the location of the sensor. If it is located too close to the exhaust system (manifold or pipes) or just connected directly to the engine; heat may be taking its toll. In fact, any electric part should be insulated with at least a 'gel' gasket. They usually become hard and brittle if not. \$\endgroup\$
    – DUKE
    Commented Aug 12, 2018 at 8:10
  • \$\begingroup\$ Haha, it's in the handlebar of an electrical scooter, so far away from the non existing exhaust pipes :-p \$\endgroup\$ Commented Aug 15, 2018 at 6:57
  • \$\begingroup\$ I know this is a very old post now, but if anyone else is looking for these, I think I have found them. I hope this may help some people...... aliexpress.com/item/… . || RM: Described as New 49E TO-92 AH49E OH49E SS49E LINEAR HALL-EFFECT IC \$\endgroup\$
    – Eric Oppel
    Commented Nov 29, 2021 at 3:02

1 Answer 1


The Americans gave credit to themselves for something invented before Hall -rediscovered it.

Gus Hall (Gus Hall, 1910-2000) Holzer (A.H.Hall, 1855 - 1938)

In 1879, physicist Holzer found Holzer effect when Hall was a rookie 24 yr old and Americans made it their own invention, now called by the Hall Effect. ( ! )

  • \$\begingroup\$ Good, so I can go ahead and find any compatible aether Holzer or Hall sensor :-) I guess we should mention this on Wikipedia? Still trying to find something that's available in the a local shop though. I found a Honeywell SS41 which seems to be quite similar as far as I can see. Now I need to find a shop that sells it, without asking 20EUR for shipping (for that price I can get a full throttle)... Thanks for clearing up the Holzer mystery (funny that they had quite similar names). \$\endgroup\$ Commented Aug 31, 2013 at 23:29
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    \$\begingroup\$ Major problem with this write up is that it was Edwin Herbert Hall (1855 - 1938) discovered the effect 1879. Here is the original paper stenomuseet.dk/skoletj/elmag/kilde9.html \$\endgroup\$ Commented Aug 31, 2013 at 23:34
  • \$\begingroup\$ I suspect that Holzer is the Chinese/Mandarin transliteration of Hall. \$\endgroup\$ Commented Aug 31, 2013 at 23:38
  • \$\begingroup\$ Hmm, I thought the names were similar. Only "Gus" doesn't sound like "Edwin" or "Herbert". I've un-answered it for now, maybe someone can solve the mystery more satisfactory. Any way I do have a practical answer, and that is that it's the same type of sensor after all :-), so if no one comes up with an better conspiracy, the kudos will go back to user28289 again... \$\endgroup\$ Commented Sep 1, 2013 at 0:09

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