Hi, I'm really new to diodes, and I'm trying to solve a circuit problem creating a voltage regulator that can operate given four extreme conditions. As far as I have calculated, not all of the conditions can be met at the same time, but I'm not quite sure so that's why I'm asking! I am using a 1N4735 zener diode, with a Zener Voltage of 6.2V, the Pz is 1.0W and I need to find a resistance value given that Vin(min) is 10V and Vin(max) is 14V. the min Load amperage is zero, and the maximum is 70mA.
**broken link removed**
If you could tell me if I'm doing this right that'd be great.
I calculated the max Amperage based off of the Pz to be
Pz = Vz*Iz , so 1.0W = (6.2V)*Iz , Iz = 161mA
If I was to find the worst case scenario to deal with Power dissipation and stay below 1.0W,
I believe that having 14Vin and 0mA load would require 7.8V drop over a 48ohm resistor
in order to keep the zener voltage. This I assume would be the maximum that R could be.
However in order to keep the Zener Voltage, then the scenario in which there is Vin = 10V and
70mA current on the load means, that 91mA goes through the diode and the V drop over the resistor
would be 3.8V meaning the smallest R could be is 42ohms.
Therefore, I think if I design a circuit in which the Resistance is between 42 and 48 ohms I should be
able to meet the conditions required.
Does this information seem correct or am I missing something critical? Any help would be appreciated.
Thanks so much!