9 Volt 2 Amp PSU with 78S09

The circuit will work without the extra components, but for reverse polarity protection a 1N5400 diode is provided at the input, extra smoothing being provided by C1. The output stage includes C2 for extra filtering, if powering a logic circuit than a 100nF capacitor is also desirable to remove any high frequency switching noise. More: There is little to be said about this circuit. All the work is done by the regulator. The 78S09 can deliver up to 2 amps continuous output whilst maintaining a low noise and very well regulated supply.

The circuit described is a power supply configuration utilizing the 78S09 voltage regulator, which is designed to provide a stable output voltage of 9V with a maximum current output of 2A. The inclusion of a 1N5400 diode at the input serves an essential function of reverse polarity protection, ensuring that the circuit remains safe from damage in the event of incorrect power supply connections. The diode allows current to flow in the correct direction while blocking any reverse current that could potentially harm the regulator or other components.

Capacitor C1 is employed at the input stage to enhance the stability of the voltage supply by smoothing out any voltage fluctuations, which can occur due to variations in the power source or load changes. This capacitor is critical in maintaining a steady input voltage to the regulator, thus contributing to the overall performance and reliability of the circuit.

In the output stage, capacitor C2 is utilized for additional filtering. This capacitor helps to further reduce ripple voltage and noise, ensuring that the output voltage remains clean and stable, which is particularly important when powering sensitive electronic circuits. For applications that involve logic circuits, the addition of a 100nF capacitor is recommended. This capacitor addresses high-frequency switching noise, which can be generated by digital circuits, by shunting these high-frequency components to ground, thereby preserving the integrity of the output voltage.

Overall, the circuit design emphasizes simplicity and effectiveness, relying primarily on the 78S09 regulator to manage voltage regulation while the supplementary components enhance performance and protection. The combination of these elements allows for a robust power supply solution suitable for various electronic applications.The circuit will work without the extra components, but for reverse polarity protection a 1N5400 diode is provided at the input, extra smoothing being provided by C1. The output stage includes C2 for extra filtering, if powering a logic circuit than a 100nF capacitor is also desirable to remove any high frequency switching noise.

There is little to be said about this circuit. All the work is done by the regulator. The 78S09 can deliver up to 2 amps continuous output whilst maintaining a low noise and very well regulated supply. 🔗 External reference