As distinguished from the Zener diode with a multimeter

Very often, the Zener diode can be confused with. How to distinguish from the zener diode? Consider a simple circuit to a multimeter consoles, which can be used not only to distinguish from the Zener diode, but also to determine the voltage stabilizing zener (if it does not exceed 35V).zener-diode-sample

Schematic diagram of the consoles is the DC-DC converter with galvanic isolation between input and output.1Generator with pulse-width modulation (Prosperity) formed on ASIC MS34063. The galvanic isolation between the power supply and measurement part of the scheme, the reference voltage is taken from a primary winding of a transformer. For this purpose rectifier VD2. The magnitude of the output voltage (stabilization point) the selection of the resistor R3 is set.

The capacitor C4 is a voltage of about 40V. Stabilizer A2 and checked VDX Zener current parametric form Stabilizer, and multimeter, connected to terminals X1 and X2 for measuring this voltage zener.

When you connect the anode to “+”, and a cathode “-” Zener diode or an asymmetric multimeter will show a very small voltage. If connected in reverse polarity (how VDX Scheme), then the testimony of a multimeter diode will be about 40V, and for the zener voltage stabilization (provided, that it is lower than 40V).

clear, that for a symmetrical Zener voltage stabilization will be indicated at any polarity.

The transformer T1 is wound on a ferrite toroidal core of external diameter 23 mm. Winding 1 It contains 20 turns, and winding 2 It contains 35 turns of wire SEW 0,43. Important, laid at winding turn to turn. And, a primary winding wound on one of the ring, and resale – another. it is recommended not to impose one coil to another.

when you set up, instead zener VDX ​​connect resistor 10 ohms and the resistance R3 selection Earn, the capacitor C4 to the voltage established 40B.

Printed circuit board:
signet Download


  1. nemogli would you develop a signet format
    Lay , many new hams , We would be grateful. Thank you for your scheme!

    • Thank you for your attention to the project. I drew a printed circuit board and attached the bottom of the article.
      Success in device assembly!

  2. inpatient easier to use a power source 30-40 The current limiting resistor and. Although, can I so lazy, I do all this test once or twice a year…

  3. I can offer such a tester for assembly.
    only instead of the indicator, you can install a digital voltmeter.
    which will show the voltage of the Zener diode.

    I use such a device myself.

Leave a Reply

Your email address will not be published.