One way to prevent reverse polarity of the DC power supply circuit

The adjustment potentiometer RP allows for modification of the over-voltage limit setting. In the event of reversed polarity in the DC power supply, there is a risk of damaging equipment components. To mitigate this risk, a reverse polarity protection circuit can be implemented. As illustrated in Figure 13-91, when the power supply is correctly connected, the light-emitting diode (LED) VL remains off. Conversely, when the power supply is reversed, VL illuminates, and due to the presence of diode VD, protection for the electronic equipment is ensured.

The described circuit employs an adjustment potentiometer (RP) that serves as a variable resistor, enabling the user to set the desired over-voltage limit for the connected load. This feature is crucial in applications where voltage fluctuations may occur, potentially leading to damage. The reverse polarity protection circuit is essential for safeguarding sensitive components from damage due to incorrect power supply connections.

The circuit operates by integrating a light-emitting diode (LED) VL, which functions as an indicator for the polarity of the power supply. Under normal operating conditions, with the correct polarity applied, the LED remains off, signaling that the system is functioning as intended. When the polarity is reversed, the LED lights up, providing a clear visual indication of the error.

Diode VD plays a critical role in this protection mechanism. It is oriented in such a way that it becomes forward-biased only when the polarity is reversed. In this scenario, VD conducts and effectively shunts the current away from sensitive components, preventing potential damage. This design not only enhances the reliability of the circuit but also provides an intuitive user interface through the LED indicator.

Overall, the implementation of an adjustment potentiometer combined with a reverse polarity protection circuit is a prudent design choice in electronic systems, ensuring both operational flexibility and component safety.Adjustment potentiometer RP, can change the over-voltage limit setting. If the DC power supply polarity is reversed, and there may be burned equipment components, for which pow er can be installed a reverse polarity protection circuit. Circuit shown in Figure 13-91. When the power is properly connected, the light emitting diode VL does not shine. When the power is reversed when, VL lights, and because of the diode VD deadline, to protect the electronic equipment.