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I've heard somewhere that a rheostat uses two pins while a potentiometer uses three. But still, the thing i would like to know is if there's anything different with the adjustment if I wire the pots like this:

enter image description here

Or will it not matter how I wire it? Thanks!

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  • \$\begingroup\$ Theoretically these are equivalent. Practically I would go with the left one to eliminate an unnecessary loop. \$\endgroup\$ – Eugene Sh. Jul 19 '16 at 17:35
  • \$\begingroup\$ You might consider possible failure modes. What would happen in each case if the wiper connection opens or becomes highly resistive? \$\endgroup\$ – Charles Cowie Jul 19 '16 at 17:47
  • \$\begingroup\$ I see i will keep that in mind, I will also read more about potentiometers in general. Thanks. \$\endgroup\$ – Xane Jul 19 '16 at 17:49
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Electrically, these 2 circuits are equivalent. However, the advantage of the circuit on the right is that if the internal moving tap loses contact with the resistive element, the circuit still appears as a resistance rather than an open circuit. The latter can cause problems with some applications (for example, causing a voltage regulator to lose regulation or generate a large voltage). That is why most designers use the circuit on the right.

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    \$\begingroup\$ And the wiper will go momentarily open circuit when adjusted due to mechanical chatter as it slides along the resistive material. You can easily see this on an oscilloscope if you build the circuit on the left. \$\endgroup\$ – Evan Jul 19 '16 at 18:59

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