Automatic Light Controller Using 7806 circuit

Description: Voltage regulator ICs from the 78xx series deliver a stable output voltage in contrast to a highly variable input supply, provided that the common terminal is grounded. Any voltage applied above zero volts (ground) to the common terminal is added to the output voltage. This indicates that an increase in the common terminal voltage is mirrored at the output. Conversely, if the common terminal is not connected to the ground, the full input voltage will appear at the output. This feature is utilized in the current circuit.

The 78xx series voltage regulators are linear voltage regulators that are designed to provide a fixed output voltage, typically ranging from 5V to 15V, with the suffix of the part number indicating the specific output voltage (e.g., 7805 for 5V, 7812 for 12V). These devices are widely used due to their simplicity and reliability in various electronic applications.

In a typical application circuit, the input voltage is connected to the input pin of the voltage regulator IC, while the output pin delivers the regulated voltage to the load. The common terminal, or ground pin, must be connected to the circuit ground to ensure proper operation. Capacitors are often placed at the input and output of the regulator to stabilize the voltage and improve transient response. A bypass capacitor at the input helps filter out high-frequency noise, while an output capacitor enhances stability and transient response.

When designing a circuit with a 78xx voltage regulator, it is crucial to ensure that the input voltage is within the specified range for the regulator to function correctly. Additionally, the maximum output current rating of the regulator should not be exceeded to prevent overheating and potential damage to the device. Heatsinking may be required for higher current applications to dissipate heat effectively.

In scenarios where the common terminal is disconnected from ground, the output voltage can rise to the level of the input voltage, which may lead to undesired effects in the circuit. Therefore, it is essential to maintain a proper ground reference in applications utilizing the 78xx series voltage regulators to ensure stable and predictable operation.Voltage regulator ICs (78xx series) provide a steady output voltage, as against a widely fluctuating input supply, when the common terminal is grounded. Any voltage about zero volt (ground) connected in the common terminal is added to the output voltage.

That means the increase in the common terminal voltage is reflected at the output. On the other hand, if the common terminal is disconnected from the ground, the full input voltage is available at the output. This characteristic is utilised in the present circuit..