Automatic Night Lamp & Morning Alarm
• Introduction :
This circuit automatically turns on a night lamp when room
light is switched off. The lamp remains ‘on’ until the light
sensor senses daylight in the morning.
• LED is used as the night lamp. It gives bright and cool light in the
• When the sensor detects the daylight in the morning, amelodious
morning alarm sounds.
• The circuit utilises light-dependant resistors (LDRs) for
sensing darkness and light in the room.
• A light dependent resistor or photo resistor is a resistor
whose resistance decreases with increasing incident light
• The LM555 is a highly stable device for generating accurate
time delays or oscillation. Additional terminals are provided
for triggering or resetting if desired.
• 555 timer is used in monostable or astable configuration
MUSIC GENERATOR UM66 :
• General Description:
• UM66 is a pleasing music generator IC which works on a supply
voltage of 3V. the required 3V supply is given through a zener
regulator. its out put is taken from the pin no1 and is given to a
push pull amplifier to drive the low impedance loud speaker.
• There is setup to generate input DCvoltage to circuit
• stepdownTransformer,Bridge rectifier, voltage regulator is used
• The output of rectifier is given to the 7806 voltage regulator
• zener diode ZD limits the voltage to a safer level of 3.3 volts.
• BC548 is used as push pull amplifier