1. Potentiometers and Rheostats
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2. Variable Resistors -- Potentiometers
Potentiometer – a three-terminal resistor whose value can be adjusted (within set limits) by the user
Rac = Rab + Rbc
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3. Construction
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4. Setting the Value of Resistance
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5. Potentiometer Taper Linear – resistance varies at a constant rate
Nonlinear – resistance changes at an increasing rate
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6. Potentiometer Ratings
Resistance Rating
Printed in straightforward manner: 5 k
Printed as code: 502 = 50 x 102 = 5 k
First two digits are the digits in the resistance value
Third digit – number of zeros
Power Dissipation Rating – consult manufacturer's catalog
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7. Trimmer Potentiometers
low-power applications
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8. Multiturn Potentiometers
Much better resolution
Smaller percentage of change per degree of rotation
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9. Gang – Mounted Potentiometers
Two pots share the same control shaft
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10. Rheostats A variable resistance used to control current
Usually a two-terminal variable resistor
Potentiometer can be wired as a rheostat
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11. Rheostats
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