Schematic Power Amplifier and Layout

Making Electronic Circuits Alarm for anti-fire

This circuit warns the user against fire accidents.

It relies on the smoke that is produced in the event of a fire.

When this smoke passes between a bulb and an LDR, the amount of light falling on the LDR decreases. This causes the resistance of LDR to increase and the voltage at the base of the transistor is pulled high due to which the supply to the COB (chip-on-board) is completed.