The difference is in the way they capture sound waves. As far as the user is concerned, the main difference is that the condenser mic needs power - either from within the mic or from an external source (called 'phantom power'). The external source can be a stand alone phantom power unit or, more typically, from a mixer. All of our mixers supply phantom power for condenser mics. On a more general point, condenser mics tend to be more sensitive and pick up high frequencies better, whereas the dynamics tend to be more rugged.