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Does a zener diode work the same as a rectifying diode? Answered

I am making a solar charger and I can only find zener diodes and the voltage and amps I need, do they work the same as a rectifying diode? Thank You!


The answer is . . . it depends.
Azener diodewill work like a normal diode in the forward direction (i.e. it will conduct with around a 0.7V drop).
It will work like a normal diode In the reverse direction (i.e. it will block the current) UNTIL the zener voltage is reached, then it will conduct with the voltage drop that the zener is rated at.
So, if your solar cell voltage is less than the zener voltage, it will work as a normal diode. If it's greater, it won't.

What size of charger are you making (voltage and current)?

The solar panel will be 7 volts and 30ma short circuit and will charge 4 AAA's (800mah NiMH) and my zener diode is rated at 2.4v. Since the solar panel is higher voltage than my zener diode the current will flow forward but it won't flow backwards, which if it flow backwards it would cause the batteries to drain. Right? Thanks for answering so fast!

That will be fine when the batteries are charging, but when when the sun goes down and the solar cell voltage drops below 3.6V (that's the 6V batteries minus the zener voltage) the batteries will discharge through the zener. Any small plastic bodied (non zener) diode will do for your circuit. Have you got an old power supply you can pull apart? That will have diodes in it.

diodes and rectifiers are bassicly the same thing!!! a rectifier is just a high power diode!!! if you use a zener diode that is higher than the max output of the solar cell(s) then i will (as andygadget said) act as a normal diode!!!

Can I just use a couple of the zener diodes in a row to make them more than then the output of the solar cells? Thanks!

a zener diode will have a voltage rating which is what voltage it will "regulate" so you will want to get one that is the same or slightly higher than your cells max output!!! make sure you include a schottky diode in between the battery and the cell or the battery will discharge into the solar cell at night!!!

If you did that you'd be getting 0.7 volts drop each when charging. You're going to be pretty marginal anyway, so no.

Ideally you'd use a schottky or germanium diode, which has a drop of only 0.3 volts or so, thus giving you more voltage available on the battery terminals when charging.