# help with a design on zener diodes

#### dwchino21

Joined Jun 20, 2007
2
Design a zener shunt regulator to provide a regulated voltage of about 10volts. the available 10 volts, 1-W zener of type 1N4740 is specified to have a 10 volt drop at a test current of 25mA. At this current, its Rz is 7 ohms. The raw supply available has a nominal value of 20 volts but can vary by as much as + to - 25%. The regulator is required to supply a load current of 0 to 20mA. design for a minimum zener current of 5 mA.

A) find Vz0
B) calculate the required value of R
C) find the line regulation. what is the change in Vo expressed as a percentage, corresponding to the + to - 25% change in Vs?
D) find the load regulation. By what percentage does Vo change from the no load to the full load condition?
E) what is the maximum current that the zener in your design should be able to conduct? what is the zener power dissipation under this condition?

#### dwchino21

Joined Jun 20, 2007
2
i need help because i dont even know where to begin with this problem.
1) I dont understand even how to draw a graph out without numbers.
2) dont even know what a zener shunt regulator is or looks like

#### niftydog

Joined Jun 13, 2007
95

#### Papabravo

Joined Feb 24, 2006
16,775
i need help because i dont even know where to begin with this problem.
1) I dont understand even how to draw a graph out without numbers.
2) dont even know what a zener shunt regulator is or looks like
You forgot to mention that your textbook, class notes, and instructor have had nothing to say on this topic. Is that correct?

Edit: I went to the hyperphysics site and it should give you what you need.