Building a circuit on a breadboard

A breadboard is a device for testing temporary electronics projects. Components used to test a circuit can be reused for other projects. None of the components are damaged.

Almost all people start to learn electronics using breadboard because it is the simplest way of making circuit. The photograph shows a typical small breadboard which is suitable for beginners building simple circuits with one or two ICs (chips).


Connections on Breadboard

Breadboard has many tiny sockets or holes arranged on a 0.1’’ grid. The leads or terminals  of most of the components like resistors, diodes, transistors, etc. can be pushed straight into the holes.

A breadboard has 4 rows of holes at the top and 4 rows at the bottom and there are several columns of holes in the middle.

There are two groups of vertical columns in the middle part, as you see in the picture below it has been separated by a blue rectangular block.

None of the rows and columns are linked to one another.

The holes in rows are linked horizontally and column holes are linked vertically.


Converting a circuit diagram to a breadboard layout is not straight forward because the arrangement of components on breadboard looks quite different from the circuit diagram. When putting parts on breadboard you must concentrate on their connections, not their positions on the circuit diagram.

Building a Circuit on Breadboard(Dark Detector using transistor)

Get following components:

NPN transistor- BC547 or BC147 or BC548

Resistor- 100K


Light emitting diode(LED)

Light dependent resistor(LDR)

Connecting wires- Use single-core plastic-coated wire of 0.6mm diameter (the standard size)-You can use wire that is used for Computer Networking.

6V battery (4 -AA size battery)