The document presents a mini project on an automatic temperature-controlled fan developed by students from the College of Engineering, Munnar. It details the components used, including thermistors and triacs, and explains their functions within the circuit designed to regulate fan speed based on temperature changes. The project is currently in progress, with the circuit successfully implemented at the breadboard level.

1. Mini project presentation
AUTOMATIC TEMPERATURE
CONTROLLED FAN
Abhilash.K.M(02)
Abin Baby(03)
Ajith Kumar R(04)
Bineesh Babu P(10)
College of Engineering Munnar

2. Mini project by
Students of
College of Engineering, Munnar
College of Engineering Munnar

3. INTRODUCTION
Ordinary fan regulators
College of Engineering Munnar
Electronic fan regulators

4. Why automatic temperature
controlled fan?
College of Engineering Munnar

5. BLOCK DIAGRAM
AC supply
230 V, 50Hz
Increase in
temperature
Bridge Rectifier
High Gain
Amplifier
230 V
AC
College of Engineering Munnar
Thermistor
Triac
Comparator
Optocoupler

6. Components Used
*Thermistor
*IC LM324
*IC µA741
*Resistors
*Zener diodes
*Optocoupler (MOC3011)
*Triac(BT 136)
College of Engineering Munnar

7. CIRCUIT DIAGRAM
College of Engineering Munnar

8. LM324
* 4 OpAmps in a
single IC
College of Engineering Munnar

9. * Basically an opto-isolator, designed to
transfer electrical signals by utilizing light
waves to provide coupling with electrical
isolation between its input and output.
*The main purpose of an opto-isolator is
to prevent high voltages or rapidly
changing voltages on one side of the
circuit from damaging components or
distorting transmissions on the other side.
College of Engineering Munnar
Schematic diagram of an
opto-isolator showing
source of light (LED) on
the left, dielectric barrier
in the center, and sensor
(phototransistor) on the
right.

10. • A thermistor is a type of resistor
• resistance varies significantly
with temperature
• used as current
limiters, temperature sensors, self-resettin
g overcurrent protectors, and
self-regulating heating elements
College of Engineering Munnar

11. • speed controls for electric fans
• TRIACs are bidirectional and so current can
flow through them in either direction.
•
TRIACs can be triggered by either a positive or a
negative current applied to its gate electrode.
• Once triggered, the device continues to conduct
until the current drops below a certain
threshold, called the holding current.
College of Engineering Munnar

12. OUR PROGRESS
We have designed and wired the circuit on the bread board level, and the output
is obtained upto 2 stages.
REFERENCE
Wikipedia, electronicsforyo
u.com
COST
250 rs
College of Engineering Munnar

13. College of Engineering Munnar