Regulated Power Supply
A regulated DC voltage source is obtained from a AC voltage source is easily by rectification. AC voltage is of 230V r.m.s. is easily available. This voltage is step downed by a transformer. Then rectified by diodes. If a center taped transformer is used only two diode is sufficient for full wave-rectification. If transformer is not a center taped bridge rectifier is used. After rectification the voltage is DC but contains high ripple. A LC or RC filter is used at the output to filter the high ripple voltage. Now this voltage can be used for DC supply. But this DC source is not regulated means if the input AC voltage changes output also changes. To get a regulated output zener diode regulation and Voltage Regulator may be used.
Voltage regulators come in integrated circuits in a variety of ranges. Regulators are of four types
1. Fixed output voltage regulators: positive or negative output voltage
2. Adjustable output voltage regulators: positive or negative output voltage
3. Switching regulators
4. Special regulators
We use 7806 and 7812 for positive fixed Regulated power supply.