Direct Current is when electrons flow continously from a positive to a negitive area through a conductor. A DC circut is made up of a generator(a powersource), a conductor(like a wire), and a resisotor( the place the energy is used). All DC circuits have a constant voltage and current. There are three types of DC circuits series, parallel, and complex these are explained below.
Parallel circuits have multiple resistors, this means there are many paths for the current to flow down. The total current is the sum of each resistor's current. Resistors in parallel circuits have equal voltages, all voltages are equal. The amount of each voltage in each resistor equals the total voltage.
Resistance in a complex circuit has to be found in multiple steps. First you would have the parallel resistance. Then add the the parallel resistance to each of the resistances of the other resistors. After this divide the total voltage by the total resistance to find the total current. To find individual voltage of each resistor multiple the total current by resistance in each resistor.