Power Supply Circuit With Zener Diode

As a blogger life is miserable i can just about afford an old banger with a knackered battery.

Power supply circuit with zener diode.

Instances of power supply failure are normally seen as when the power supply stops working and there is no output. A zener diode is a special type of diode designed to reliably allow current to flow backwards when a certain set reverse voltage known as the zener voltage is reached. One of the main application of a zener diode in circuits is it can be used to obtain constant reference voltage values. The simple circuit diagram is displayed below where the transistor is being used as emitter follower.

Zener diode circuit for a simple regulated power supply. It provides a maximum of 100 ma for the load which is sufficient to power my small cd player in the car. Some zener diodes have a sharp highly doped p n junction with a low zener voltage in which case the reverse conduction. However this stability and accuracy is generally good enough for the zener diode to be used as a voltage regulator device in common power supply circuit in the figure below.

The zener diode is used in its reverse bias or reverse breakdown mode i e. Zener diode regulator circuit zener voltage 12 6v. When using such a circuit the current needed from the zener resistor potential divider must be calculated. The diodes anode connects to the negative supply.

Zener diodes are manufactured with a great variety of zener voltages and some are even variable. As the voltage across the zener diode has always a constant for any applied voltage values above the zener voltage it can obtain a fixed voltage value in a circuit which has a variable or fluctuating power supply. Zener diode operation please take note of the zener diode s orientation in the above circuit. The way out of it is to use a zener diode circuit with a seris pass transistor.

This zener diode power supply circuit produces constant 4 7 v dc from 10 v to 14 4 v input. From the i v characteristics curve above we can see that the zener diode has a region in its reverse bias characteristics of almost a constant negative voltage regardless of the value of the current flowing through the diode. These circuits using discrete parts can be in the form of of permanently fixed or constant voltage or stabilized adjustable output voltage. All linear power supply circuits which are designed to produce a stabilized constant voltage and current output fundamentally incorporate transistor and zener diode stages for getting the required regulated outputs.