capacitor
I am making a homemade capacitor for a project. I got the plans from this link. I am making the 60μF simple electrolytic capacitor. I have made it, but:
How would I charge the capacitor with a power source? Also, I have a 5V power source, so…
Will this 60μF capacitor hold this charge?
Could I disconnect the capacitor from the power source after it's charged, and will it still hold it's charge for a short amount of time?
How long do I wait for the 5V power source to charge the capacitor?
If it's fully charged there's no current. When not or partly charged there will be current if you apply a voltage to it. The current curve depends on how your voltage source is connected. If you supply a constant current the voltage will rise linearly, if you charge over a resistor it will rise exponentially. That's because the rising voltage will cause the voltage drop over the resistor to become smaller and smaller, and hence the current through it will also decrease. A lower current means that charging goes slower.
How fast the capacitor charges depends on both the resistor's and the capacitor's value. The larger the resistor the slower the capacitor charges, and it also charges slower if the capacitance is greater. The exponential curve is said to have a time constant \$RC\$. After about \$5 \times RC\$ the capacitor is charged to 99%.
9V. The capacitor's rating has nothing to do with it, that only determines how high a voltage you can apply. Just look at what voltage is available, and that's 9V. Just take care that the capacitor is fit for the supplied voltage. You can safely charge a 16V capacitor to 9V, but not to 25V.
Capacitor choice is largely a matter of losses, yes. The capacitance value needs to be large enough to keep the midpoint more-or-less-fixed, with low ESR and ESL also being important. Under some transient conditions the midpoint can (and will) move around, so it's important to keep derating in mind as well. 50% voltage derating is well within reason (using 400V caps with a total DC input of 400V, for instance).
For AC-application capacitors (i.e. film caps), the ESR is often implied in the dissipation factor datasheet parameter, which is the relationship between ESR (resistive loss) and reactance:
\$ DF = \omega C \cdot ESR = \dfrac{1}{Q} \$
\$ \omega = 2 \pi f \$
It will usually be specified at a given frequency, which allows you to calculate the ESR.
Electrolytic capacitors generally have large ESL by nature of their construction vs. film capacitors, limiting their usefulness at high frequency. Film capacitors also have some self-healing capability under dielectric breakdown scenarios which make them a 'robust' choice in half-bridge designs.
Best Answer
If you really want to know, use a volt meter to measure these things yourself. Given that the behavior depends on the specifics of what you've actually built, it will give you much better data than what a web forum can guess at.