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An **SMPS (Switched-Mode Power Supply)** converts AC to DC through several steps. Here's a simple breakdown of the process:
1. **AC Input**: The SMPS first receives an **AC (Alternating Current)** input from the power source (like the wall outlet).
2. **Rectification**: The AC voltage is passed through a **rectifier**. This is a set of diodes that only allow the positive part of the AC waveform to pass through, converting the AC to **pulsating DC** (direct current). This means that the voltage is now only in one direction but still fluctuates.
3. **Filtering**: The pulsating DC from the rectifier still has ripples or fluctuations. To smooth out these fluctuations and make the output more stable, the DC voltage is passed through a **filter** (typically a capacitor). This reduces the ripples and provides a smoother DC voltage.
4. **Switching**: This is where the "switched-mode" part comes in. The SMPS uses a **high-speed switch** (usually a transistor) to rapidly turn the DC on and off. This switching action creates a **pulsed DC** that is easier to transform to different voltages. The frequency of switching is typically much higher than the AC frequency (several kHz or even MHz).
5. **Transformation**: The pulsed DC is passed through a **transformer**. The transformer adjusts the voltage level, either stepping it up or down, depending on the design of the SMPS.
6. **Filtering and Regulation**: After the transformer, the output is still pulsed DC. Another **filtering stage** smooths the voltage further, and **feedback control** regulates the output to ensure the correct and stable DC voltage is provided.
7. **DC Output**: Finally, the result is a stable **DC voltage** that can be used to power electronic devices.
In short, an SMPS converts AC to DC by rectifying the AC, filtering it, switching the DC to a higher frequency, using a transformer to adjust the voltage, and then regulating the output to ensure a steady DC voltage. This method is efficient because it uses high-frequency switching, reducing energy losses compared to traditional linear power supplies.
1. **AC Input**: The SMPS first receives an **AC (Alternating Current)** input from the power source (like the wall outlet).
2. **Rectification**: The AC voltage is passed through a **rectifier**. This is a set of diodes that only allow the positive part of the AC waveform to pass through, converting the AC to **pulsating DC** (direct current). This means that the voltage is now only in one direction but still fluctuates.
3. **Filtering**: The pulsating DC from the rectifier still has ripples or fluctuations. To smooth out these fluctuations and make the output more stable, the DC voltage is passed through a **filter** (typically a capacitor). This reduces the ripples and provides a smoother DC voltage.
4. **Switching**: This is where the "switched-mode" part comes in. The SMPS uses a **high-speed switch** (usually a transistor) to rapidly turn the DC on and off. This switching action creates a **pulsed DC** that is easier to transform to different voltages. The frequency of switching is typically much higher than the AC frequency (several kHz or even MHz).
5. **Transformation**: The pulsed DC is passed through a **transformer**. The transformer adjusts the voltage level, either stepping it up or down, depending on the design of the SMPS.
6. **Filtering and Regulation**: After the transformer, the output is still pulsed DC. Another **filtering stage** smooths the voltage further, and **feedback control** regulates the output to ensure the correct and stable DC voltage is provided.
7. **DC Output**: Finally, the result is a stable **DC voltage** that can be used to power electronic devices.
In short, an SMPS converts AC to DC by rectifying the AC, filtering it, switching the DC to a higher frequency, using a transformer to adjust the voltage, and then regulating the output to ensure a steady DC voltage. This method is efficient because it uses high-frequency switching, reducing energy losses compared to traditional linear power supplies.