POWER-SUPPLY.pptx

POWER SUPPLY  A power supply is the heart of all electronics equipment. It converts AC input power line to DC output voltage. It is the one, which supplies the desired voltage or current in a circuit. BLOCK DIAGRAM FILTER A B C D Each...

POWER SUPPLY  A power supply is the heart of all electronics equipment. It converts AC input power line to DC output voltage. It is the one, which supplies the desired voltage or current in a circuit. BLOCK DIAGRAM FILTER A B C D Each of the blocks is described in more detail below: Transformer - steps down high voltage AC mains to low voltage AC. Rectifier - converts AC to DC, but the DC output is varying. Smoothing/Filter - smoothes the DC from varying greatly to a small ripple. Regulator - eliminates ripple by setting DC output to a fixed voltage. Dual power supply  Dual Supplies Some electronic circuits require a power supply with positive and negative outputs as well as zero volts (0V). This is called a 'dual supply' because it is like two ordinary supplies connected together as shown in the diagram. Dual supplies have three outputs, for example a ±9V supply has +9V, 0V and - 9V outputs. Schematic diagram  TYPES OF AC-DC POWER SUPPLY RECTIFIER CIRCUIT 1. Half-Wave Rectifier Circuit One rectifier diode D1 is needed and load resistor RL to conduct on one alteration in every cycle of small AC input. Schematic Diagram of Half-Wave Rectifier  Full-Wave Center-Tapped Rectifier Circuit Using this type of circuit, you’ll need a center-tapped transformer two rectifier diodes and a load resistor RL. Each of the diode supplies one-half the DC load current. Schematic Diagram of Full-Wave Center Tapped Rectifier Circuit Schematic Diagram of Full-Wave bridge type RECTIFIER CIRCUIT  The previous circuit illustration uses four rectifier diodes D1 D2 D3 D4 and a load resistor RL. Bridge circuit makes it possible to remove the center-tapped transformer. Between the two previous types of power supply (Half-wave and Full- wave center tapped), this circuit can deliver a higher current range to the load, because all of cycles are consumed by the four diodes. The operation of this rectifier circuit is different from the half-wave and full-wave center tapped. The conduction of AC. voltage starts from Line-A going to Line-B. OUTPUT FOR EACH SECTION Transformer only  The low voltage AC output is suitable for lamps, heaters and special AC motors. It is not suitable for electronic circuits unless they include a rectifier and a smoothing capacitor. Transformer +rectifier  The varying DC output is suitable for lamps, heaters and standard motors. It is not suitable for electronic circuits unless they include a smoothing capacitor. Transformer + Rectifier + Smoothing  The smooth DC output has a small ripple. It is suitable for most electronic circuits. Transformer + Rectifier + Smoothing + Regulator  The regulated DC output is very smooth with no ripple. It is suitable for all electronic circuits.  Rectifier are several ways of connecting diodes to make a rectifier to convert AC to DC. The bridge rectifier is the most important and it produces full-wave varying DC. A full- wave rectifier can also be made from just two diodes if a centre-tap transformer is used, but this method is rarely used now that diodes are cheaper. A single diode can be used as a rectifier but it only uses the positive (+) parts of the AC wave to produce half-wave varying DC  Bridge rectifier A bridge rectifier can be made using four individual diodes, but it is also available in special packages containing the four diodes required. It is called a full-wave rectifier because it uses all the AC wave (both positive and negative sections). 1.4V is used up in the bridge rectifier because each diode uses 0.7V when conducting and there are always two diodes conducting, as shown in the diagram below.  Bridge rectifiers are rated by the maximum current they can pass and the maximum reverse voltage they can withstand (this must be at least three times the supply RMS voltage so the rectifier can withstand the peak voltages). Please see the Diodes page for more details, including pictures of bridge rectifiers. D1 D2 D3 D4 Unregulated Bridge-type Power Supply Regulated Power Supply Regulated Power Supply Foil Pattern 2014- 15 PCB SIDE SIZE: 1.5”X2” TSHI- Main COMPONENT SIDE A. Regulated Power Supply Schematic diagram B. Regulated Power Supply Foil Pattern and Component Placement Guide C. Regulated Power Supply Wiring Diagram D. Actual Appearance