1. Electronic Components1 Power Supply - Stage 1 n Mains voltage has to be reduced 1 - Transformation + - + - 120 V AC 30 V AC 4:1

2. Electronic Components2 Power Supply - Stage 2 n Alternating voltage has to be converted to DC 2 - Rectification Half wave rectification Load 30 V AC 9.6 V DC

3. Electronic Components3 Power Supply - Stage 2 n Alternating voltage has to be converted to DC 2 - Rectification Half wave rectification Load -9.6 V DC 30 V AC

4. Electronic Components4 Power Supply - Stage 2 n Alternating voltage has to be converted to DC 2 - Rectification Full wave rectification RLRL 30 V AC 19.1 V DC

5. Electronic Components5 Power Supply - Stage 3 n Fluctuating voltage has to be smoothed 3 - Filtered RLRL R L = 5.1 k  C = 33  F V out = 40V DC with 1V ripple

6. Electronic Components6 Power Supply - Stage 3 (Filtering) RLRL RSRS When first turned on capacitor acts as a short. The surge current can damage diodes. This can be reduced by adding a surge resistor.

7. Electronic Components7 Power Supply - Stage 3 (Filtering) RLRL A more effective (although more costly) way is to use an inductor to oppose the changes in current. The capacitors in the LC  filter oppose changes in voltage.

8. Electronic Components8 Power Supply - Stage 4 n Voltage has to be smoothed further 4 - Regulation Zener diode gives constant base voltage. Thus base current is constant and so will be the collector and emitter currents. RLRL

9. Electronic Components9 Graymark 808 Power Supply n Power supply was built from a kit. n Has two 0 - 15V and one 5V n Also has three protoboards n Ideal for doing analogue and digital lab projects

10. Electronic Components10 Graymark Power Supply n Bottom plate shows transformer and circuit board Circuit Board Bottom plate Transformer

11. Electronic Components11 Graymark Power Supply n Circuit board Rectifier diodes IC regulator Filter capacitor