Laser Security
Security is
a major concern in this technological era. Security alarm is a very useful
instrument, alarms can deter crime. Alarms have become standard equipment in
stores and other businesses; they are becoming increasingly common in private
homes as well.
Here is a
simple project named Laser Security illustrated below.
The Project
involves a laser Source (Semiconductor Diode), Light dependent Resistor (LDR),
a 10K Resistor, BC 547 Transistor and a Sound Source Buzzer.
When the
Laser Fall on the LDR the current directly flows to the ground and no voltage
is introduced at the base hence circuit get disconnected and no sound appears
from the buzzer in all other cases the Buzzer is ON.
Laser security is a cheap yet indispensable to tool
to protect your precious things you can integrate this system at the Door,
Windows, Drawers and everywhere that needs protection.
Circuit
Diagram
Laser Security
Working of Laser Security System
Circuit
diagram for the laser security is shown above, it comprise of LDR, A npn Transistor BC547, a 10K resistor and Buzzer.
When
transistor is biased with a 9V battery the Current enters to the base of
Transistor, that connects the Emitter and Collector and the circuit get shorted
in turn Switch on the Sound Buzzer.
What happens when laser light fall on
the LDR
When no
light is falling on the LDR the Resistance of LDR is quiet high, more than 10 K
for that reason current flow to the base of the transistor, in case when light
is falling on the LDR the resistance of the LDR drastically decreases and the
Current get ground hence no current reaches to the Base of the transistor and
Transistor behave as a open Switch
Components
Used
- Buzzer
- Transistor BC547 (npn)
- Resistor- 10 K
- Light dependent Resistor (LDR)
- Battery- 9v
- Semiconductor Laser
Applications
Used for
Security system in Home offices and Store,
You can download Proteus for trying this circuit at your computer
You can download Proteus for trying this circuit at your computer
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