@JRE The number of turns on the first primary is 85. On the second primary it's 108 turns.

Your battery (4x3.7V*3.4Ah) gives you 50Wh of energy. To charge it in 3h, you'll need a source capable of 16W continuous. USB can deliver upto 2.5W. USB 3 can deliver that kind of power, but you have to negotiate it over the USB protocol.

Can you tell me where you plan to get your "voltage and current boost converters?" That sounds real handy.

You don't connect a third speaker to a pair that way. Depending on how the amplifier is built, it will either do nothing (no sound from the third speaker,) sound awful (weak and/or distorted,) or blow up your amplifier. It might also work surprisingly well. Do you want to risk blowing up your amp to find out?

With a runtime of 21 hours, you were using an average of 2.7W. That's a long way from the amplifiers' rated 2*100W.

@ScientistSmithYT Misread that about the windings. I read it as "primary and secondary" rather than "primary and other primary."

I had a doubt in a question. The question is in a center tapped full wave rectifier with filter of 120uF and load current, find ripple factor of output.

My teacher solved this by taking load current as Idc but isn't that wrong?

@Aladdin Idc is the load current, and it is responsible for the ripple. What else would you use?

From what I understand, ripple happens due to the capacitor discharging after reaching maximum rectified voltage

I don't see any significance of Idc here....

@Aladdin The charge from the capacitor has to go somewhere. Idc is the only discharge path you have for the capacitor.

Ah okay. I get what you are saying

No load (Idc=0,) no ripple.

@rdtsc ?

Tumbleweeds blow past... Who's gonna answer that question first? It's a show-down. Fastest typer wins.

@rdtsc Which question?

@JRE I guess I forgot to give the nominal voltage and charged(max) voltage for the batteries. They are charged at 4.20 - 4.22 volts. There is a tiny voltage difference which doesn't make a difference overall in operation. My USB will allow for up to 20 watts output and minimum of 5 watts output.

@JRE Can you familiarize me with what USB protocol is?

@JRE I intend on getting my voltage and current boost converters from eBoot, and GoWoops through a 3rd party Amazon carrier. I do have enough in the budget to destroy a few amplifiers. Logically down at the basics it seems that it could work, but sometimes those logical basics are wrong in some cases. That's why I asked.

@JRE I saw your message about the transformers. I make mistakes like that as well. Even after I've looked at it several times. :)

@JRE The speaker runtime test was the speaker turned all the way up, and the volume on my phone all the way up as well. So it was running at max. So theoretically it could run longer since we know that it uses more energy when turned up louder.

@JRE I'll connect the 3rd speaker to it and tell you how it goes once I have the time. Which today is pretty slow going, so I'll most likely do it in an hour or less from now.