Absolute Beginner's Guide to A+ Certification

Multivoltage Power Supplies

Most power supplies are designed to handle two different voltage ranges:

• 10–120V/60 cycle

• 20–240V/50 cycle

Standard North American power is now 115–120V/60-cycle AC (the previous standard was 110V). The power used in European and Asian countries is typically 230–240V/50-cycle AC (previously 220V). Power supplies typically have a slider switch with two markings: 115 (for North American 110–120V/60-cycle AC) and 230 (for European and Asian 220–240V/50-cycle AC). Figure 5.2 shows a slider switch set for correct North American voltage. If a power supply is set to the wrong input voltage, the system will not work. Setting a power supply for 230V with 110–120V current is harmless; however, feeding 220–240V into a power supply ...