I've got a couple of questions I need a bit of help with, due to not working with electronics for years! And I'm having problems finding the correct formulae to find the answers I need.

**First one:**

**Second one is this:**A conventional ignition circuit with the contact breakers open and a 3 microfarad capacitor receives a voltage of 12v, state its charge in coulombs.

If the primary coil has a resistance of 5.2 ohms is included in series with the capacitor, what would the state of charge now be? (ignoring any inductance qualities)

Also state the circuits time constance and the initial charge current.

Any help would be much appreciated!

Many Thanks

Henry