Page 96 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

DC Voltage Stabilizers:
Series or Shunt regulators are frequently used for regulating the voltage of the DC power supplies. A reference
voltage is applied using a shunt regulator like Zener diode or Voltage regulator tube. These voltage stabilizing
devices start conduction at a specified voltage and they will conduct maximum current to hold the specified
terminal voltage. Excess current is diverted to ground often using a low-value resistor for dissipating the energy.
The figure shows the DC-adjustable-voltage stabilizer using IC LM317.

The shunt regulator output is used only for providing the standard
reference voltage to the electronic device called as voltage stabilizer,
which is capable of delivering much larger currents based on the
demand.

Automatic Voltage Stabilizers:
These voltage stabilizers are used on generator sets, emergency
power supply, oil rigs, and so on. It is an electronic power device used
for providing variable voltage and, this can be done without changing
the power factor or phase shift. Large sized voltage stabilizers are
fixed permanently on the distributed lines and small voltage stabilizers
are used for protection of the home appliances from the voltage
fluctuations. If the voltage of the power supply is less than the required
range, then a step up transformer is used for stepping up the voltage
levels and similarly if the voltage is greater than the required range,
then it is stepped-down using a step-down transformer.
Practical example of automatic voltage stabilizer can be observed in power supply circuits used to provide
supplies to the electronic and electronic circuits. Frequently 7805 regulator is used for providing supply to the
microcontroller based project kits as the microcontrollers operate at 5v. In this 7805 voltage stabilizer, the first
two digits represent the positive series and the last two digits represents the output voltage value of the voltage
regulator.

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CITS : E & H - Electronics Mechanic - Lesson 48 - 55