Q1: What is the value of a capacitor labeled 102?

Often the capacitor will simply be marked with a two digit number printed on the body such as "10" for example. This indicates that it is a 10pF capacitor. However you may find some capacitors marked "10n" and this capacitor will have a value of 10nF (ie 10,000pF), this is sometimes seen on polystyrene types and some resin dipped ceramics. To make matters rather more confusing, when we eventually arrive home with a plastic bag full of components keen to construct a circuit we find that many capacitors are marked with a three digit code such as "103" or "104" and some others have a three digit code plus a letter on the end such as "101K" or "102K". The capacitors marked with three digits are similar to resistors in that the first two digits represent the value in pF (as above) and the third digit is the multiplier with a letter to indicate the Tolerance. So "100" would be 10pF multiplied by zero i.e. 10pF. "103" is 10pF multiplied by 1000 ie 10,000pF or to put is another way 0.01 microfarads. "471K" would be a 470pF capacitor with a 10% Tolerance.