zener diode question

nutt7

Member
I need a 27 volt 1/2 watt zener (mtzj27b) for my receiver. I can't find the exact part number in town, but I can find a different manufacturer (nte5033a)with the same basic specs (27v 1/2w). I tried to compare data sheets but it seems they compare slightly different aspects of the diode. I would obviously want the right part, but I would also like to get it done today if this other one will work fine (assuming it fits physically). The diode is used as a voltage regulator for a relay.

Thanks,
eric
 
I would not know why that would not work fine, but when I replace a zener that has gone bad, I like to double the wattage - as in go to a 1 watt part in this case.
 
nutt7

"I would not know why that would not work fine, but when I replace a zener that has gone bad, I like to double the wattage - as in go to a 1 watt part in this case."

+1

You never know unless you measure the current in the zener circuit how close to max they are running the zener diode...And if it failed once...

So that is why you double the wattage rating. Just to be on the safe side. The wattage rating is the max for diode and if it is running close to the max rating then it can be prone to failure and doubling the rating just gives a safety margin.
 
Last edited:
I guess there is a reason why it went out, so doubling wattage may prevent i from happening again too soon. I still think I will just get the 1/2w ones in town since I cant find a 1w. If it dies again, shame on me, but it only cost me $1 and 10 minutes of time.
 
Just for a relay voltage regulator, I suspect specs are not at all critical. You can series wire 2 zeners if you can't get the voltage you need, e.g., a 12V and a 15V will substitute for a 27V - and that doubles up the wattage, more or less.
 
Back
Top Bottom