Answer:
A breadboard is a base which is used to make organised, neat, simple and temporary circuit connections.
Normally, in a circuit, the elements are connected to each other by twisting the wire ends.
But this kind of twisting and connecting has some drawbacks:
1. Many connections at the same point cant be made easily because twisting many wires together is cumbersome.
2. Elements like transistors, resistors, capacitors etc are difficult to connect in a circuit.
3. The circuit becomes complex due to the irregular arrangement of elements.
4. Connecting and disconnecting elements require many twists and unwindings which will damage the wire..thus the circuit cant be changed or corrected for errors often.
These are overcome using breadboard.
It has a line full of holes which are at equal potential. So, for examle, if one wants to connect a voltage source across a resistor, the ends of resistor must be connected to the ends of supply.
In a breadboard, the two terminals of resistor are plugged in two holes in different lines,say lines 1 and 5.
One terminal of supply is plugged in a hole in one of the lines ie in line1.
The other terminal is plugged into a hole in the other line5. Thus the circuit is complete.
But how is this possible?
A line with five holes is connected underneath by a conducting metal.
Therefore when one terminal touches it, the current passes through it and brings the underlying metal to the potential of the wire.
Thus when an other terminal is inserted into a hole in the same line, it touches the metal with potential equal to that of wire and the terminal is in effect connected to the wire. this is how circuit connections are made. Each of the lines like 1A to 1E and 3A to 3E have five holes each and each line has same potential.
This is how electrical conduction is made in a breadboard.