Mumbai University > Information Technology > sem 3> Analog and Digital Circuits

Marks: 5M

Year: Dec15

REGULATED POWER SUPPLY:

• Regulated power supply is an electronic circuit that is designed to provide a constant dc voltage of predetermined value across load terminals irrespective of ac mains fluctuations or load variations.

• A regulated power supply essentially consists of an ordinary power supply and a voltage regulating device, as illustrated in the figure. The output from an ordinary power supply is fed to the voltage regulating device that provides the final output. The output voltage remains constant irrespective of variations in the ac input voltage or variations in output (or load) current.
• Figure given above shows the complete circuit of a regulated power supply with a transistor series regulator as a regulating device. The ac voltage, typically 230 Vrms is connected to a transformer which transforms that ac voltage to the level for the desired dc output.
• A bridge rectifier then provides a full-wave rectified voltage that is initially filtered by a ∏ (or C-L-C) filter to produce a dc voltage. The resulting dc voltage usually has some ripple or ac voltage variation. A regulating circuit use this dc input to provide a dc voltage that not only has much less ripple voltage but also remains constant even if the input dc voltage varies somewhat or the load connected to the output dc voltage changes. The regulated dc supply is available across a voltage divider.