REGULATED D.C POWER SUPPLY

What is power a regulated d.c power supply?

A regulated dc power supply (also know a linear power supply), is an embedded circuit consisting of various component such as transformer, diode, capacitors, resistors and the voltage regulator which can be zener diode or LM70s IC.

Today almost every electronic device need a dc power supply for its smooth operation and the need to be operated within certain power supply range. This required dc voltage (which can be derived from a battery) or directly from AC mains through a regulator.

 The diagram below shows a 5volts regulated dc power supply.

List of components

1.     230v – 12volts 1A stepdown transformer

2.     1A bridge rectifier

3.     Polarized capacitor 470uf  50v

4.     Non-polarized capacitor 0.01uf

5.     Voltage regulator LM705

6.     Resistor 1k

7.     Led

Working principle

The heart of this regulated dc power supply is the LM705 as it determines the constant output voltage.

A 230v alternating current is input to the primary of the transformer and its being stepdown to 12v AC, the bridge rectifier converts the AC voltage to DC which passes through filtering capacitors C1 and C2 then the regulator regulates the dc voltage to 5volts constant output which is also filtered by capacitor C3. Led serve as an indicator and resistor 1k is used to limit the current entering into the led.