<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV><BLOCKQUOTE type="cite"><BLOCKQUOTE type="cite"></BLOCKQUOTE></BLOCKQUOTE></DIV><FONT class="Apple-style-span" face="Geneva">Hello Harry and Ian,</FONT><DIV><FONT class="Apple-style-span" face="Baghdad"><FONT class="Apple-style-span" face="Geneva"><BR class="khtml-block-placeholder"></FONT></FONT></DIV><DIV><FONT class="Apple-style-span" face="Baghdad"><FONT class="Apple-style-span" face="Geneva">I just wanted to thank you guys for your helpful tips last month on working with the linear Hall-effect sensors. There was such a sensor in the throttle of the electric scooter I was trying to repair. As it turned out, the scooter's no-go problem was indeed a result of a failed Hall-effect IC, and I was finally able to get a perfect substitute for the original part from Allegro Semiconductor. In fact, they sent me a handful of free samples, so I've got some extra ones now to play with. I'm not sure what I'll do with them yet -- a potless CV or wah pedal comes to mind. Anybody have any other ideas?</FONT></FONT></DIV><DIV><FONT class="Apple-style-span" face="Baghdad"><FONT class="Apple-style-span" face="Geneva"><BR class="khtml-block-placeholder"></FONT></FONT></DIV><DIV><FONT class="Apple-style-span" face="Baghdad"><FONT class="Apple-style-span" face="Geneva">The part I ended up using is an Allegro A1302EUA "continuous-time, ratiometric, linear Hall-effect sensor". Allegro also has the A1301EUA, which has a different sensitivity (higher sensitivity, I think) to magnetic fields. They are little three-pin mini-SIP devices, and look just like small transistors. They cost about a dollar each in small quantities, although none of our usual suppliers seem to have them in stock these days. The connections couldn't be any simpler: Ground, + Supply, and Output. Internally, the device's output is a simple emitter follower. The output is proportional to the device's proximity to a magnetic field. This field can be easily provided by small permanent magnets placed near the IC, or a field from a nearby electromagnet, such as an energized motor coil.</FONT></FONT></DIV><DIV><FONT class="Apple-style-span" face="Geneva"><BR class="khtml-block-placeholder"></FONT></DIV><DIV><FONT class="Apple-style-span" face="Baghdad"><FONT class="Apple-style-span" face="Geneva">I don't know what killed the original one in the scooter -- It didn't happen while operating the machine, but probably happened while I was messing around with the wiring (without a schematic, of course!). I may have inadvertently shorted the wrong pin directly to the 36 Volt supply or something like that (the Hall-effect device's upper voltage limit is around 6 Volts or so).</FONT></FONT></DIV><DIV><FONT class="Apple-style-span" face="Geneva"><BR class="khtml-block-placeholder"></FONT></DIV><DIV><FONT class="Apple-style-span" face="Geneva">Michael Bacich</FONT></DIV><DIV><FONT class="Apple-style-span" face="Geneva"><BR class="khtml-block-placeholder"></FONT></DIV><DIV><FONT class="Apple-style-span" face="Geneva"><BR class="khtml-block-placeholder"></FONT></DIV><DIV><FONT class="Apple-style-span" face="Geneva"></FONT></DIV><DIV><FONT class="Apple-style-span" face="Verdana" size="3"><SPAN class="Apple-style-span" style="font-size: 11px;"></SPAN></FONT></DIV></BODY></HTML>