This is first mini emergency light of my son. It is very small, use LED display when power outage,use transistor instead relay use AA battery charger.
The siren circuits are what importance in various alarm system. For example, the emergency alert, burglar alarm circuits, Fire alarm circuits, Timer , sensor controls, etc. Today I would like to introduce the simple and economical simple siren circuits. It is suitable for beginners. My son will gradually build this circuit onto the PCB layout. Look at below! 4 Circuits.
This is simple signal injector circuit, used two transistors join together as astable multivibrator, signal output frequency 1,000Hz in square wave form.
This regulator is 0-50v variable power supply circuit,3A that adjust output voltage 0V to 50 volts, and important is the overcurrent protection at 3 A.
This is IC 4060 Timer circuit. When rises time that is set, Suppose set 5 minutes time. after all time to 5 minutes. the circuit will emit a sound of buzzer once.