Hi All,

Are two 15V Zener diodes in series basically the same as a 30V zener???

 

The are the same except for a possible difference in their combined impedances at breakdown (the zener impedance). You have to look at the respective data sheets to see.

 

The other way they're different is if the circuit also makes use of their .7V forward breakdown...obviously two diodes is going to give you two voltage drops instead of one!

 

The other way they're different is if the circuit also makes use of their .7V forward breakdown...obviously two diodes is going to give you two voltage drops instead of one!

So put a 1n914 or 1n400x in inverse parallel with the two series Zeners...

 

Mike - heh, there may or may not be a few high-powered bass amps with exactly that arrangement lumped into them and doused in hot glue floating around the East Bay...

 

Two (equal) zeners in series also have twice the dissipation as one.