CHAPTER 14 ■ VARIABLE RESISTORSTurning the potentiometer control dial has no effect on the resistance between the first and third leads.
Swapping the black and red test probes on the potentiometer makes no difference, just like a fixed resistor.
Measuring the Variable Resistance of a Potentiometer
Connect the multimeter test probes to the first and middle leads of a potentiometer to display the changing
resistance as the potentiometer control dial is turned (see Figure 14-6). As the dial is turned to the left, the
resistance to the first lead decreases and the resistance to the third lead increases. The reverse occurs as the
dial is turned to the right, the resistance to the first lead increases and the resistance to the third lead decreases.
Figure 14-5. Hook probes connected to the first and third pins of a trimpot to measure maximum value
Figure 14-6. Hook probes connected to the first and middle pins of a trimpot to measure varying values