It spreads light in the dark and remains off in the light.
Components:
1) 2 NPN Transistors (Code no: BC547)
2) 1 LED
3) 1 LDR (Light Dependent Resistor)
4)...
It indicates the water level of tank just before the over flow.
Components:
1) 3 LED's
2) 4, 100 Ohms Resistors
3) 4 NPN Trasistors (Code: BC547)
4) 1 Buzzer
5) 9 Volts Battery
Circuit...
