We are going to build a water level indicator circuit using 555 timer IC. This is a useful project which detects the water level and gives a signal to the user indicating that the water has reached the desired level.

Almost every electronic hobbyist must have faced a scenario where he or she must measure the frequency of signal generated by a clock or a counter or a timer. We can use oscilloscope to do the job, but not all of us can afford an oscilloscope. We can buy equipment for measuring the frequency but all these devices are costly and are not for everyone.

Voltage doubler is the circuit where we get the twice of the input voltage, like if we supply 5v voltage, we will get 10 volt at the output. Generally transformers are there to step-up or step-down the voltage, but sometimes transformers are not feasible because of their size and cost. So here is the quick, easy and practical solution to double the voltage, using 555 timer IC.

In this instructable i will explain how to build a simple 555 circuit that will blink a led and sound a buzzer, this has many application for example you can connect an LDR between the power source and the circuit and then put it in your closet where it is dark and when someone opens the closet the alarm will sound

555 time IC is very powerful and versatile IC, it can be used in many forms. In this tutorial we are going to see how a 555 IC can be used as Audio Amplifier. A low power audio signal can be amplified using 555 Timer IC.