Resistors are marked with (typically) four colored bands. These bands provide a code that can be used to determine the fvalue of the resistance. The meanings of the colors and band placements are provided in Figure 11.4.1.
Figure11.4.1.[GENERATE OWN FIGURE] Resistor color codes. Thus, a resistors with a Green-Violet-Orange-Silver code has a resistance of \(57\times 10^3\Omega = 57\text{k}\Omega \pm 10\%\text{.}\)
Potentiometers (or pots) typically have three terminals: Two are the ends of a fixedc resistor and one is the ’wiper’, as pictured in Figure 11.4.2.
Figure11.4.2.[GENERATE OWN IMAGE] a) Physical design, b) what’s inside, c) schematic symbol This design allows the potentiometer to be used as a variable resistor, where the resistance varies between the wiper terminal and each of the fixed terminals as the knob is rotated. Before using aany potentiometer, ensure that you are sure of the role tqaken by each of the terminals, as there can be variation in the terminal layouts.
Subsection11.4.3Switches
The SPST (single pull, single throw) switch has two terminals, while the SPDT (single pull, double throw) switch has three terminals as shown in Figure 11.4.3.
Figure11.4.3.[GENERATE OWN FIGURE] The SPST switch is meant to flip between a closed circuit and an open circuit, depending on the switch position. The SPDT is meant to flip between connection A and connection B, depending on the switch position. Always verify the switch operation before incorporating it into your circuit. Many prototyping boards have built-in switches available, as shown in Figure 11.4.4.
Figure11.4.4.[GENERATE OWN IMAGE]
Subsection11.4.4Wires, Cables, and Connectors
Banana Plugs (Figure 11.4.5) are typically at the ends of an insulated wire containing a single conducting path. The cable color is irrelevant to the behavior of the wires, though some thought should be used when choosing colors to assist with wiring organization. Alligator clips can be attached to banana wires, allowing them to clip to a component.
