Water Level Sensor

The described surface-mount device (SMD) circuit employs the ULN2803A, a high-current Darlington transistor array, to function as a water level sensor for monitoring and managing liquid levels in tanks or reservoirs. The circuit is optimized for compactness and precision, making it suitable for industrial, agricultural, and domestic applications.

Circuit Overview

The ULN2803A is an 8-channel Darlington transistor array that can drive high-current loads while interfacing directly with low-current control signals. Each channel in the IC is equipped with a pair of Darlington transistors, allowing for higher current gains, as well as built-in base resistors, flyback diodes, and open-collector outputs. These features are leveraged in the circuit to handle the electrical signals generated by the water level detection mechanism.

The circuit is divided into the following functional blocks:

1. Water Level Probes and Input Interface
2. Signal Processing with ULN2803A
3. Indicator and Control Outputs
4. Power Supply