● The primary purpose of a power supply is to convert AC to DC.
● Power supplies built with transformers are not isolated from the power source.
● Transformers are used in power supplies for isolation and to step up or step down the voltage.
● A rectifier circuit converts incoming AC voltage to pulsating DC voltage.
● The basic rectifier circuits are half-wave, full-wave, and bridge.
● Half-wave rectifiers are simpler and less expensive than either full-wave or bridge rectifiers.
● The full-wave rectifier is more efficient than the half-wave rectifier.
● The bridge rectifier can operate without a transformer.
● To convert pulsating DC voltage to a smooth
DC voltage, a filter must follow the rectifier in the circuit.
● A capacitor in parallel with the load is an effective filter.
● A voltage regulator provides constant output re- gardless of load and input voltage changes.
● The voltage regulator is located after the filter in the circuit.
● The two basic types of voltage regulators are the shunt regulator and the series regulator.
● The series regulator is more efficient and therefore more popular than the shunt regulator.
● Voltage multipliers are circuits capable of providing higher DC voltages than the input volt- age without the aid of a transformer.
● Voltage doublers and voltage triplers are voltage multipliers.
● Voltage dividers can reduce high voltages to lower voltages.
● A crowbar is a circuit designed for overvoltage protection.
● A fuse protects a circuit from a current overload.
● Fuses are classified as either normal or slow-blow.
● Circuit breakers perform the same job as fuses but do not have to be replaced each time there is an overload.