Voltage regulators in series,Transistor series voltage regulator

Voltage regulators in series

In electronic most unavoidable part at the power supply section will be the regulators, most of the devices are work in DC power, so regulation of the ripples mixed signal will be a must thing.

And the definition of regulation is the measure of the change in the voltage magnitude between the receiving and sending end of a component and the regulator can provide a constant voltage at any conditions.

 When we discuss voltage regulators, we need to know about two types of regulators such as linear regulators and switching regulators.

In this article, we explain the linear series regulator type, at the linear regulator type we have series and shunt.

What is the purpose of a good voltage regulator

  • To maintain a constant DC output voltage 
  • To remove the ripples voltage, form due to the rectification processor didn’t remove by the filter circuit 
  • To provide a protective function from short circuit, current limiting, and overload, maintain an unchanging voltage value at the output.


Series voltage regulator 

block diagram of the series voltage regulator
block diagram of the series voltage regulator

We mentioned earlier series voltage regulators will belong to linear regulators, image shows the block diagram of the series voltage regulator, which we can see every section will be connected in series with each other.


And the main thing we need to consider for a series regulators are the placement of variable element, which we can see at the series circuit, variable resistor placed series with the load, by changing the resistance value, causes the voltage dropped across it can be varied to ensure that the voltage across the load remains constant.


If in case output voltage increases, the comparator circuit provides a control signal to the output section to reduce the magnitude of the output voltage.


And what happened when output reduces than desire level, comparator circuit provides a control signal, series control element increases the voltage level output.


This is the process to maintain the output at a particular limit.


The cause and effect two of the blocks help to maintain regulation at a level (such as comparator and control element).


Transistor series voltage regulator (emitter follower voltage regulator)

When we see into the connections, collector, and emitter terminals are series with the load.

We have a Zener diode, which is acts as a reference voltage element, and the transistor is used as the variable resistor.


Moving on to the working we need two cases

Case1; Input or supply voltage increases

        Input or supply voltage increases, it will cause the output voltage, and this result increase in base-emitter voltage.

Case2; Load and output voltage changes

        When the current is increased due to the decrease of load resistor, voltage output decrease will cause an increase of base-emitter voltage.

These effects must be compensated by the increase in input current.

Transistor series voltage regulator
Transistor series voltage regulator

Advantage of the series regulator

  • They had a high level of performance 
  • They had low noise 
  • They maintain the signal at low ripples
  • They had low transients

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