Potentiometer Resistance Chart

As is described in the section on sound, the sound that we hear doesn't correspond linearly to the amount of electric power used; it instead corresponds logarithmically. A volume control knob must, therefore, have a non-linear change in resistance as well. We graphed the resistance of the potentiometer for every 5 degrees of rotation of the knob in order to measure this effect. To measure the resistance across the potentiometer, we connected a digital multimeter, set to 20 ohms (the maximum resistance of the resistor), to its center lead and to one of its two side leads. We then used a protractor to move the knob in 5 degree increments, noting the resistance every 5 degrees. This is the graph resulting from that measurement:

Here is the data used to form that graph:

Resistance (kW) Angle (degrees)

97.5
97.5
97.5
97.6
97.4
97.2
93.5
84.5
74.5
67.8
62
60.6
55.9
48.3
40.8
35.8
30.1
21.5
17.7
16.4
15.7
14.7
13.9
13.4
12.6
11.9
11
10.5
10.1
9.8
9
8.4
7.8
6.9
6.5
5.8
5.2 225
220
215
210
205
200
195
190
185
180
175
170
165
160
155
150
145
140
135
130
125
120
115
110
105
100
95
90
85
80
75
70
65
60
55
50
45

Resistance (kW)	Angle (degrees)
97.5 97.5 97.5 97.6 97.4 97.2 93.5 84.5 74.5 67.8 62 60.6 55.9 48.3 40.8 35.8 30.1 21.5 17.7 16.4 15.7 14.7 13.9 13.4 12.6 11.9 11 10.5 10.1 9.8 9 8.4 7.8 6.9 6.5 5.8 5.2	225 220 215 210 205 200 195 190 185 180 175 170 165 160 155 150 145 140 135 130 125 120 115 110 105 100 95 90 85 80 75 70 65 60 55 50 45