This circuit functions as a zener diode and has the advantage of having a variable zener voltage. It is sometimes
called hybrid zener diode. It is more versatile and more adaptive than fixed value zener diodes.
The total resistance of this circuit is 20 up to 50 ohms and its maximum dissipation is negligible. The zener voltage is variable from 3V up to 25V with the potentiometer P1.
Make sure that the maximum current through
the circuit does not exceed 100 mA !
Parts Placement Layout
The figure above shows the hybrid zener diode in the most classical application of a zener diode - as a voltage regulator.
The series resistor in the circuit is very important - it dissipates the excessive voltage so
that the output voltage remains at a constant level. You have to use the standard procedure in determining the value of the series resistor for a zener diode voltage regulator circuit.
Electronic Circuits volume 1.0 - Circuit Nr. 94
The complete data of the electronic circuit described above can be found in the following book and is available from Amazon.com.
Click on the image to view the book.