Page 51 - Build Your Own Transistor Radios a Hobbyists Guide to High-Performance and Low-Powered Radio Circuits
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FIGURE 3-17 Audio transformers.
Single-turn variable resistors or potentiometers are shown in Figure 3-18. These
generally are used for volume control, especially the ones shown on the right.
FIGURE 3-18 Variable resistors or potentiometers.
Multiple-turn variable resistors or potentiometers will be used for adjusting
frequency in an oscillator or levels of a signal. They offer a more precise
adjustment than single-turn types (Figure 3-19). The markings can be of two types.
One is the exact value in ohms, such as 10K = 10,000
n
or 10 k
n
. And the other can be a three-digit code where the last digit means the number of
zeros added after the first two numbers, for example, 204 = 20 plus 4 zeros =
200000 = 200,000
