Water Pump Controller Circuit Assignment

The circuit you provided is a basic water pump controller circuit used to control the water level in an overhead tank. Let's go through the components and their functions:

1. Step-down Transformer: The step-down transformer is used to convert the input voltage (typically 220V AC) to a lower voltage suitable for the circuit (usually 24V AC). It ensures the safety of the circuit by reducing the voltage.

2. Floats: The circuit uses two floats, namely the upper float and the lower float, to sense the water level in the tank. Floats are buoyant devices that rise or fall with the water level. They are connected to the micro switches.

3. Micro Switches: The micro switches are connected to the floats and act as sensors to detect the water level. When the floats are in a particular position due to the water level, the micro switches are activated and change their states.

4. 24V AC Double-Changeover Relay: The relay is used to control the operation of the water pump. It has three output terminals: Common (COM), Normally Open (NO), and Normally Closed (NC). When the relay is not energized, the COM terminal is connected to the NC terminal. When the relay is energized, the COM terminal is connected to the NO terminal. This switching action controls the power supply to the water pump.

The operation of the circuit can be summarized as follows:

• When the water level is below the lower float, both floats are in the downward position, and both micro switches are open. This de-energizes the relay, and the water pump remains off.

• As the water level rises, the lower float eventually reaches its upward position, closing its associated micro switch. This energizes the relay, and the power supply to the water pump is established.

• When the water level continues to rise, the upper float eventually reaches its upward position, closing its associated micro switch. This breaks the circuit and de-energizes the relay, turning off the water pump.

• If the water level drops below the upper float, the micro switch associated with the upper float opens, and the relay remains de-energized. The pump will not turn on until the water level rises above the upper float again.

This simple water pump controller circuit ensures that the water pump operates only when the water level is between the upper and lower float positions, maintaining a desired water level in the overhead tank.