A DC circuit is a circuit with a direct current. A circuit consists of many different components and each of these has a symbol which we use so that anyone which any language can see and identify the component just by its symbol, some of these are:
This means there is no language barrier when it comes to working with circuits. The use of symbols also allow us to use them (in diagrams) before setting up circuits so we know how the circuit is laid out and what needs to go where to obtain what results.
In a series circuit there is one loop of current from the power supply at the negative terminal back to positive terminal, this means that there are no extra components in an extended branch coming off any of the series wires.
Parallel circuit In a parallel circuit the circuit has extra sets of components coming out from the original series loop.
The diagram on the top is the series circuit which has all the components in one loop without any extra wires connecting any external components; we say that all the components are in series with the power supply. The diagram on the bottom is a parallel circuit which has extra wires connected a lamp to the original series circuit. We say that the lamp is in parallel with the other lamp.
By Munawar Ali Khan