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Need help for selection of Inductor and capacitor for electrical project

Ranveer07

New Member
Hello, I have Piezo electric energy harvester , and producing Vpp=20 (10+ - 10-) , f= 20 hz , and I= current around in microamp. I want to store this energy or forward to load , for that I am using first Inductor than full wave bridge rectifier and than capacitor . Which value range around suitable for Inductor and capacitor ?

Thanks in advance
 

billybob

Active Member
For the capacitor, it doesn't really matter. Just make sure it can withstand the voltage and have enough Farads to filter the wave completely. Bigger is normally better in this situation.
As for the inductor I assume you are intending for this to be a choke coil to block further ac?
Do you understand the principle of the inductor?

Also I may be wrong, but I think putting the inductor in front of the rectifier defeats the purpose. I would put it after the cap.

What is this for?
 

gophert

Well-Known Member
Most Helpful Member
For the capacitor, it doesn't really matter. Just make sure it can withstand the voltage and have enough Farads to filter the wave completely.
This isn't a very good answer. You don't want "enough farads". You want to size the capacitor so the microamps delivered from the piezo device can charge the capacitor with current while building up a reasonable (usable) voltage. That means, you'd need a 100,000,000 clicks of the piezo to get to some target voltage on a 100uF capacitor whereas, you'd get your charge on one click on a 1pF capacitor. That's why the term "engineering" is used to develop a technical design. You (Ranveer07) need to define some parameters that you expect and then decide how you'll get there.

Note: in the example above, the charge in the 100uF capacitor will likely leak before you get to 100,000,000 clicks and you never reach the voltage of a single click at 1pF. These ideas seem much better in ideal systems and schematics than they do in real life actual designs. Many investor dollars, family members' savings and even company R&D dollars have been spent/squandered trying to harvest piezo energy for purposes or by methods that our current reality cannot support.
 

shortbus=

Well-Known Member
Most Helpful Member
Many investor dollars, family members' savings and even company R&D dollars have been spent/squandered trying to harvest piezo energy for purposes or by methods that our current reality cannot support.
But I saw it on Youtube!
 

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