TOUCH SENSOR CIRCUIT
USING BJT
APPLIED PHYSICS PROJECT
This presentation explores the design and operation of a touch sensor
circuit utilizing a Bipolar Junction Transistor.
DONE BY:
Patlolla Annapurna Roll No: 24261A6648
Kanthi Sena Roll No: 24261A6655
A.Nikhil Roll No: 24261A6601 B.Tech CSM Sem II
GUIDED BY: S.K.C Acharyulu Department of Physics and Chemistry
Mahatma Gandhi Institute of Technology
Introduction to Touch
Sensors
Touch sensors are electronic devices. They detect physical touch or
contact. They act like switches without moving parts. These sensors are
common in smart devices and industrial systems.
Electronic Devices Switch-like Function
Detect physical contact or Respond to pressure or
proximity. electrical disturbance.
No Moving Parts
Enhances durability and reliability.
Background Theory: Types of Touch Sensors
Understanding different touch sensor types is crucial. Each type has unique working principles. This impacts their application
and performance in various scenarios.
Resistive Touch Sensors Capacitive Touch Sensors
Work by pressure. Detect electrical disturbance.
Used with stylus/gloves. Multi-touch support.
Durable & cost-effective. High sensitivity.
Requires more pressure. Doesn9t work with gloves/stylus.
Working Principle of Touch
Sensor
The touch sensor operates like a simple switch. When no touch is
detected, the circuit remains open. This prevents current from flowing.
No Touch
Circuit is open; no current.
Finger Touches
Human skin acts as a conductor.
BJT Switches ON
Transistor allows current flow.
LED Activates
Current flows, LED glows.
Circuit Diagram and
Components
The touch sensor circuit design is straightforward. It integrates essential
electronic components. Each component plays a vital role. This ensures
proper functionality.
6 1 2
Components Resistors
Breadboard 220 ' and 270 ' for
Key parts for the
current control.
circuit. For prototyping the
circuit.
1
BC 547
NPN BJT transistor.
Procedure for Simulation
The simulation process is systematic. It allows for virtual assembly and testing. This ensures correct circuit behavior before
physical implementation.
Place Components
On virtual breadboard (ThinkerCAD).
Make Connections
Follow the circuit diagram precisely.
Check Connections
Verify accuracy; proceed if correct.
Touch Sensor
Use mouse pointer; observe LED.
Reset
Rerun simulation as needed.
Simulation Link :-
https://ade2-iitr.vlabs.ac.in/exp/bjt-transistor/simulation.html
Result & Conclusion
The experimental results confirmed circuit functionality. The LED
activated upon touch. This validates the BJT's role in the touch sensor
circuit.
1 Successful Response
Touch sensor circuit reacted to input.
2 LED Activation
LED lit up with touch input.
3 BJT Validation
Confirmed BJT's role in the circuit.
Applications of Touch
Sensors
Touch sensors are versatile. They are integrated into many modern
technologies. Their ability to detect contact without mechanical parts
makes them ideal. They offer convenience and advanced control.
Mobile Devices Home Musical
Smartphones, tablets,
Automation Instruments
touch screens. Smart home control Control pads and
systems. interfaces.
Robotics
Collision detection
and navigation.
References
Our research relied on reliable resources. These sources provided foundational knowledge. They were crucial for the project's
success. We used virtual tools for simulation and experimentation.
Applied Physics Lab
Virtual Labs Manual
ThinkerCAD Online platform for simulated Guidance for practical experimental
Virtual breadboard and circuit experiments. procedures.
simulation.
THANK YOU!
We appreciate your attention to our presentation. We hope you gained
valuable insights. We are open to any questions. Your feedback is
welcome.
Patlolla Annapurna Roll No: 24261A6648 , Kanthi Sena Roll No:
24261A6655 , A.Nikhil Roll No: 24261A6601 B.Tech CSM 3 Sem II
