I intentionally did not ask about why use an oscillator to charge a capacitor. That IS a fair question.

 

I intentionally did not ask about why use an oscillator to charge a capacitor. That IS a fair question.

I intentionally did ask: https://forum.allaboutcircuits.com/threads/super-capacitor-charging.210894/post-2041636

 

Now I get an inappropriate response, one that I see as mocking my question. I do not like being mocked by WBahn!
This site does post rules about responses.

 

To fully charge a 3 volt capacitor from a 3 volt source will require a higher voltage, as has been well explained by others. To deliver a reasonable charge "without an oscillator" can be done using a classic "full wave voltage doubler" circuit and a manually operated polarity reversal switch in the supply voltage circuit connection. So no oscillator would be involved, nor even any transformer or inductive components.

 

This thread provides the reasoning for choosing a higher voltage to use for charging a capacitor. At least in the practical realm.

Not necessarily if it's being charged with a current-limited voltage source (e.g. a power supply).

 

The trade-off is always charging current versus charging time. AND, even a current limited charging voltage source, the actual current is also limited by the charging voltage.

 

The trade-off is always charging current versus charging time.

Really?

 

REALLY!! To reduce the charging time for a capacitor you must increase the rate of charge. OR REDUCE THE AMOUNT OF CHARGE. To reduce the refueling time of circle-track race cars they pressurise the fuel cans with compressed air. So the gas comes out of those ten gallon cans not by gravity alone, but also aided by a whole lot of compressed air pressure. So a goof in the pits during refueling can spray gas all over. quite a few years ago I worked for a race car driver for a while. Doing electrical stuff, not refueling. During refueling I was the guy with the CO2 extinguisher in hand. THAT can be a very tense job!!
Pushing hard while charging a capacitor causes heat. pushing too hard causes TOO MUCH HEAT and that causes very rapid expansion sometimes.

 

Now I get an inappropriate response, one that I see as mocking my question. I do not like being mocked by WBahn!
This site does post rules about responses.

Merely pointing out that the question has already been asked.

 

The trade-off is always charging current versus charging time

So efficiency is never a concern?

 

You guys are being a little pedantic, I think. I know the TS haven't been responding, but it seems that we all know the equipments and schemes to charge (and how to charge) a supercapacitor.

 

Merely pointing out that the question has already been asked.

I tend to repeat relevent questions that have not been answered.
No offense intended, but certainly an answer from the thread starter is needed.

 

Here's a video done by my cousin TonyR1084, no longer a member of AAC by his own choice. It involves a very brief moment of contact between two wires. During that period of contact four AA batteries charge the cap to nearly full voltage. It didn't take long to charge the 2000µF caps high enough to power a Super Bright LED (SBLED) through a 200Ω resistor. Once charged it didn't take long for the caps to discharge through the resistor and SBLED. The whole point is two fold: First, the caps didn't take long charge to near full 6 volts. Second, the charged caps provided enough energy to light the SBLED to near full brightness briefly, then to dim out as the charge drained off.