Zener Diode

[Gerhard Nerge]

Hi

I'm in need of a 18 Volt 5 Watt Zener diode, I have only 18 Volt 1 Watt
Zener diodes.
My question is, can I put 5 one Watt Zener diodes parallel to make it 5 Watt
?

Thank you in advance
Gerhard.

 

[Palindr☻me]

The short answer is no: the first to fire will take the entire load.

You can do some form of balancing by adding series resistance to each
zener, but that loses the voltage stability you want.

Use the zener to establish the voltage at the base of a 5 watt power
transistor, and use the emitter as your stablized voltage source.

Or the OP could put half a dozen 3v 1W zeners in *series* to produce the
desired voltage.

Or use a three terminal regulator eg LM7818.

etc..