Working on...

your queries, use contact form

2 Sept 2020

what is voltage regulator?

 What is voltage regulator?

How zener diode works as voltage regulator?

What is load regulation and line reuglation?

We well known the fact, all electronics devices or elements (i.e. diode transistor, basic IC) and circuit required A.C as well as D.C power source but many times we refer D.C. constant power source to the circuit for their operation. So D.C source carry dry battery or cell etc. but it is more expensive as compare to conventional D.C. power supply. The regulated D.C. power supply is made to converting A.C supply to D.C supply. The essential elements of regulated power supply are Rectifier, Filter and Voltage Regulator. The fluctuations in power supply may cause electronic devices to damage or give false/irrelevant output. Hence many electronic devices need the power supplies that provide constant voltage irrespective of changes in normal power supply. Regulator is such a device which is used to maintain the voltage of normal power supply constant.

Line regulation: - It is the ability of power supply to maintain the specified output voltage with varying input voltage. It is the ratio of change in output voltage of power supply to the change in input voltage.

Line regulation = Δ Vout / Δ Vin


Load regulation: - It is the ability of power supply to maintain the specified output voltage under varying load conditions i.e. under no load and full load conditions. Load regulation is calculated by formulae

Load regulation =  (VNL - VFL) / VFL

where, NL means No load, and FL means full load


Zener Voltage Regulator: - For voltage regulator application, zener diode is always used in reverse biased mode, i.e. anode is connected to –ve terminal of battery and cathode is connected to +ve terminal of battery. For proper operation of zener diode voltage regulator, input voltage must be greater than zener voltage (e.g. if zener diode of say 8 voltage is used, input voltage must be greater than 8 volts to operate zener diode in reverse bias). 

Figure: Zener Diode as Voltage Regulator


As the load current increase, the zener current decreases so that the input current remains constant. As the input voltage increases, more zener current will flow through the zener diode. This increases the input voltage, and also the voltage drop across the resistor Rs, but the load voltage V0 would remain constant. Thus, a zener diode acts as a voltage regulator and the fixed voltage is maintained across the load resistor RL.

Here is the practical implementation of zener diode voltage regulator on breadboard. 



No comments:

Post a Comment