The document describes a light sensitive trigger circuit project that uses a 555 timer IC, resistors, capacitors, an LDR, and relay. The circuit diagram and components used are explained, including descriptions of resistors, capacitors, photoresistors and the 555 timer IC. When light falls on the LDR, the circuit is completed which triggers the 555 timer IC to provide an output that activates the relay. The project aims to develop a circuit that can trigger an action based on light intensity.

1. ELECTRICALS AND ELECTRONICS
WORKSHOP (EEW)
[2110012]
PROJECT REPORT
Prepared by: Riddhi N Patel
[160630107092]
Dhara Patel
[1606301070 ]
Guided by: Prof. Tejal Tandel

2. Prof. Sanjay Sir
TOPIC: Light Sensitive Trigger
INTRODUCTION:
CIRCUIT DIAGRAM:

3. PARTS USED:
 Resistors R1 – 33k , R2 - 1k,
R3 – LDR , R4 – 10k
 Capacitors C1 – 10 pF
 Semiconductors D1 – 1N 4148
IC1 – 555
12V/1Co Relay
IC Socket

4. COMPONENTS DESCRIPTION:
1. RESISTOR: A linear resistoris a linear, passive two-
terminal electrical component that implements electrical
resistance as a circuit element. The relation b/w current and
voltage is represented by Ohm's law: I = {V R}
CIRCUIT SYMBOL:
2.CAPACITOR: A capacitor (formerlyknown as
condenser) is a an electric field. The forms of practical capacitors
vary widely,but all contain at least two electrical conductors
Separated by a dielectric (insulator).
CIRCUIT SYMBOL:
3.PHOTORESISTOR(LDR):
A photoresistor or light dependent resistor (LDR) is a resistor
whose resistance decreases with increasingincident light intensity.
LDRs or Light Dependent Resistors are very
useful especially in light/dark sensor circuits.
Normallythe resistance of an LDR is very high,
sometimes as high as 1000 000 ohms, but when
they are illuminated with light resistance drops dramatically.

5. CIRCUIT SYMBOL:
4. IC 555(TIMER IC):
WORKING:

7. RESULT:
CONCLUSION: