Ohms law

[Pinnie]

You asked a question that only matters to engineers.

Ah. The sheep wandered from the pasture.

If you can do basic Ohms law calcs and understand how a series and parallel circuit work that's all you need to get started.

This is good news

A good grasp of electrical theory is important to being an above average electrician, but I got to be a way better electrician by learning circuitry, hand/off/auto switches, remote start/stop, playing with relays and making some sense of schematics than I ever did learning obscure ohms and three phase calculations. You'll never need to calculate impedance to get through a day at work.

thank you that’s comforting.

 

[ptonsparky]

Not to sound lazy, but how much effort versus return do you think is there. I am maybe a third through mikes theory book and it feels like a lot of brain power to learn. Plus the theory well is deep, how much theory knowledge do I need? There’s only so many hours in the day. I’m more than capable of mastering theory, but I don’t think I want to be an engineer. I’m leaning towards focusing on studying business. I’m weak there.

Education only hurts while you're getting it.

You don't have to be an engineer to appreciate the nuances of theory and understanding business operations should be approached the same way.

I'm an electrician. I disliked the motor classes while in school. I never gave a thought to business.

I ended up being a business owner that worked with motors. Hindsight.

 

[LarryFine]

Got it. Just the properties of the physical components of the capacitor cause it to charge at a high rate at “lower” voltages correct?

Almost. The charging/discharging currents happen because the voltage is varying.

On a steady DC voltage, a capacitor blocks current passing through it, while an inductor passes current with little impedance. On AC, a capacitor's impedance drops as the frequency increases, while
an inductor's impedance rises as the frequency increases.

In power circuits, since we deal with a constant frequency, we only care about the impedances at 60Hz. The formulae for capacitance are reciprocals.

Is the capacitor stopping the flow current in a series circuit?

Yes, if the voltage is not varying, because its current must flow through every component in a series circuit.

This is the 90 degrees out of phase as you describe in a purely capacitive circuit.

Bingo.

Gotcha. The capacitor’s plates swap charge polarity during positive and negative parts of the cycle.

Bingo. Caps made for use on AC are called non-polarized.

 

[Pinnie]

Almost. The charging/discharging currents happen because the voltage is varying.

Is the wax paper rated to only for current to pass through at over a certain voltage?

On a steady DC voltage, a capacitor blocks current passing through it, while an inductor passes current with little impedance. On AC, a capacitor's impedance drops as the frequency increases, while
an inductor's impedance rises as the frequency increases.

So the rate of the cycle is what affects the ampacity of a capacitor.

Do caps and inductors do the opposite thing to each other, and switch roles on dc and ac?

Yes, if the voltage is not varying, because its current must flow through every component in a series circuit.

Is that because the voltage on both sides of the cap are the same?