Acid-rain-monitor
A simple bridge rectifier and a 12-V regulator power the MOSFET sensing circuit. The unregulated output of the bridge rectifier operates the drain solenoid via switch S1. The sensor itself is built from two electrodes: one made of copper and the other of lead. In combination with the liquid trapped by the sensor, the electrodes form a miniature lead-acid cell whose output is amplified by MOSFET Q1. The maximum output produced by the prototype cell was about 50 µA. MOSFET Q1 serves as the fourth leg of a Wheatstone bridge. When sensed acidity causes the sensor to generate a voltage, Q1 turns on slightly, causing its drain-to-source resistance to decrease. This resistance variation results in an imbalance in the bridge, which is indicated by meter M1.
The circuit operates using a bridge rectifier that converts alternating current (AC) to direct current (DC), providing the necessary power for the MOSFET sensing circuit. The 12-V regulator ensures that the voltage remains stable and suitable for the operation of the components involved. The bridge rectifier's unregulated output is utilized to control a drain solenoid through switch S1, allowing for the activation or deactivation of the solenoid based on the circuit's requirements.
The sensor is designed using two electrodes: one of copper and the other of lead. When immersed in a specific liquid, these electrodes act as a miniature lead-acid cell, generating a voltage in response to the acidity of the liquid. This generated voltage is typically low, with the prototype cell producing a maximum output of approximately 50 µA. To enhance the signal strength, MOSFET Q1 is employed to amplify the output from the sensor.
In this configuration, MOSFET Q1 also functions as an integral part of a Wheatstone bridge circuit, which is used for precise measurements of resistance changes. As the acidity of the liquid is sensed, the voltage generated by the sensor causes MOSFET Q1 to partially turn on, resulting in a decrease in its drain-to-source resistance. This change in resistance creates an imbalance in the Wheatstone bridge, which can be detected and measured by meter M1. The output from meter M1 provides a visual indication of the acidity levels, allowing for monitoring and control within the system. Overall, this circuit design effectively combines sensing and amplification techniques to achieve accurate measurements in applications requiring acidity detection.A simple bridge rectifier and a 12-V regUlator powers the MOSFET sensing circuit. The unregUlated output of the bridge rectifier operates the drain solenoid via switch S1: The sensor itself is built from two electrodes: one made of copper, -the other oflead. In combination with the liquid trapped by the sensor, the electrodes form a miniature lead/acid cell whose output is amplified by MOSFET Ql.
The maximum output produced by our prototype cell was about 50 p.A. MOSFET Q1 serves as the fourth leg of a Wheatstone bridge. When sensed acidity causes the sensor to generate a voltage, Q1 turns on slightly, so its drain-to-source resistance decreases. That resistance variation causes an imbalance in the bridge, and that imbalance is indicated by meter Ml.
The circuit operates using a bridge rectifier that converts alternating current (AC) to direct current (DC), providing the necessary power for the MOSFET sensing circuit. The 12-V regulator ensures that the voltage remains stable and suitable for the operation of the components involved. The bridge rectifier's unregulated output is utilized to control a drain solenoid through switch S1, allowing for the activation or deactivation of the solenoid based on the circuit's requirements.
The sensor is designed using two electrodes: one of copper and the other of lead. When immersed in a specific liquid, these electrodes act as a miniature lead-acid cell, generating a voltage in response to the acidity of the liquid. This generated voltage is typically low, with the prototype cell producing a maximum output of approximately 50 µA. To enhance the signal strength, MOSFET Q1 is employed to amplify the output from the sensor.
In this configuration, MOSFET Q1 also functions as an integral part of a Wheatstone bridge circuit, which is used for precise measurements of resistance changes. As the acidity of the liquid is sensed, the voltage generated by the sensor causes MOSFET Q1 to partially turn on, resulting in a decrease in its drain-to-source resistance. This change in resistance creates an imbalance in the Wheatstone bridge, which can be detected and measured by meter M1. The output from meter M1 provides a visual indication of the acidity levels, allowing for monitoring and control within the system. Overall, this circuit design effectively combines sensing and amplification techniques to achieve accurate measurements in applications requiring acidity detection.A simple bridge rectifier and a 12-V regUlator powers the MOSFET sensing circuit. The unregUlated output of the bridge rectifier operates the drain solenoid via switch S1: The sensor itself is built from two electrodes: one made of copper, -the other oflead. In combination with the liquid trapped by the sensor, the electrodes form a miniature lead/acid cell whose output is amplified by MOSFET Ql.
The maximum output produced by our prototype cell was about 50 p.A. MOSFET Q1 serves as the fourth leg of a Wheatstone bridge. When sensed acidity causes the sensor to generate a voltage, Q1 turns on slightly, so its drain-to-source resistance decreases. That resistance variation causes an imbalance in the bridge, and that imbalance is indicated by meter Ml.