Study Unit Understanding and Using Electronic Diagrams

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voltage of 120 volts, so the step-down transformer in Figure 1 has a turns ratio of 120 V/18 V = 6.67:1. Since the second-ary voltage is 18 volts and the maximum current is 2 amps, you know that the maximum volt-amp (VA) rating of the transformer is 18 V 2 A = 36 VA. A replacement trans-former would need to have the same secondary voltage, but

  Ratios, Voltage