Contributions

?Water level controllers are quite common nowadays. This circuit is based on popularly used IC555 IC. Water level controller circuits have these advantages: Most  the circuit only display the amount of water present in circuit,   but this circuit will "on" and "off" the motor according to the level of water present in tank. It will not automatically stop the motor when tank is fill but it will "on" the motor when water in tank reaches below a specific point. It can be easily installed in over headed tanks because of less components used in circuits. It prevents the wastage of water due to over flow of tank. Can be operated with the help of 12V battery or adaptors (converts 230V AC to 12V DC) readily available in markets.

This circuit can be used in various projects where we require the counting. Like in doctors’ clinic or hospitals, in restaurants, in customer care offices where long  queue is there and we want to stop the rush at the counter. This system is very effective where man power is less. In this you have to provide a token to the person and the person has to wait for its turn which can be displayed on the 7 segment display. With the help of this circuit we can maintain the silence and the person will also be informed about their turn.

This circuit is based on 4026, a Johnson counter IC commonly used in digital display. It has a 5 stage Johnson decade counter with decoder which convert the Johnson code to a 7 segment decoded output.