Page 74 - Testing Electronic Components

10= 10 Volt
10V= 10 Volt
BZX85C18=18 Volt 1 watt zener diode (you have to refer to Philips ECG
Semiconductors Transistor Cross Reference Guide)

BZY85C18=18 Volt 1/2 watt zener diode
Note: There is also part number such as BZVXXXXX where you have to
find it from Philips ECG SEMICONDUCTOR BOOK.

1N4746= 18 Volt 1 watt zener diode.
Sometimes a normal signal glass type diode you may think is a zener
diode thus you will not get the exact measurement. If you have confirmed
that the diode you want to measure is zener diode then you can proceed to
use my method to accurately test it. For your knowledge, a zener diode
with 2.4 volt to 12 volt should have two readings when test with an
analogue meter set to times 10K ohm range. But these readings are not
shorted reading!

A 1N4733A zener diode

Let me guide you, when you put your meter probes across the zener diode
of 2.4 volt using the times 10 k ohm range, one way will show a full scale
reading (red probe to cathode and black probe to anode) which mean the
pointer will point towards the 0 ohms scale, if you now connect the probe
the other way (black probe to cathode and red probe to anode) the pointer
will point to around 2- 4 ohms!

If both ways of testing caused the pointer to point to zero ohms then the
zener diode is considered shorted. When you measure a 5.1 volt zener
diode, as usual one way will point to zero ohms while the other way will
show a higher resistance which is in the 20 to 60 ohms. These are the

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