zener diode power dissipation calculation

[hitome]

like to know how to calculate the zener diode power consumption. the zener in my circuit is used to make over voltage protection. As from the datasheet, I can only see max ratings of forward current and forward voltage. But in actual, how can I calculate. this datasheet not enough info as some of the datasheets say forward current and voltage at 25degC. But the one I'm using doesn't have.

 

[julioreye]

i have a datasheet that may be can useful. it doesn't have information about power of each one,although you can multiplicate Iz*Vz. regards.

 

[pauloynski]

Confusing question. Is it a crowbar protection? If so the zenner should not be allowed to conduct under normal operation of the circuit and the power dissipation should be zero. When an overvoltage happens it will conduct and your circuit must limit the total current to a safe point. Then, maximum rates against time should be taken into account. Could you clarify how do you intend to use it?

 

[hitome]

hi, thanks for the answers. Case closed. Yeah, it applied as clamping vtg and no need to take count in operation condition. Thanks to all.