Desktop power supply circuit diagram

The diagram shows the circuit of the desktop power supply. Regulator IC LM317T is arranged in its standard application. Diode D1 guards against polarity reversal and capacitor C1 is an additional buffer. The green LED (LED1) indicates the status of the power input. Diode D2 prevents the output voltage from rising above the input voltage when a capacitive or inductive load is connected at the output. Similarly, capacitor C3 suppresses any residual ripple.

Connect a standard digital voltmeter in parallel with the output leads to accurately set the desired voltage with the help of variable resistor VR1. You can also use your digital multimeter if the digital voltmeter is not available. Switch on S1 and set the required voltage through preset VR1 and read it on the digital voltmeter. Now the power supply is ready for use.
The circuit can be wired on a common PCB. Refer Fig. 2 for pin configuration of LM317 before soldering it on the PCB. After fabrication, enclose the circuit in a metallic cover as shown in Fig. 3. Then open the cabinet of your PC and connect the input line of the gadget to a free (hanging) four-pin drive power connector of the SMPS carefully.

LS-550 BFG power supply specifications

• ATX12V 2.2
• Single 12V Rail
• SATA Connectors
• PCI Express Ready
• Efficiency: > 80% Typical
• Silent 135mm Intake Fan
• BFG Thermal Control Technology
• Protection Circuitry
• MTBF: > 100,000 Hours at 25°C
• 550W Continuous Rated at 40°C
• Dimensions: 8.6cm W x 15cm H x 16cm D (3.4″ W x 6″ H x 6.4″ D)

BFG power supply DC Output

• +3.3V = 24A
• +5V = 24A
• +3.3V +5V Combined Load Wattage = 140W
• +12V = 42A
• -12V = 0.3A
• +5Vsb = 2.5A

LS-550 Box content

• 1 x 550 Watt Power Supply Unit
• 1 x US Power Cable
• 1 x User’s Guide
• 4 x Mounting Screws

BFG LS550 Connectors

• 1 x 24-Pin (20+4-Pin) Motherboard Connector
• 1 x 8-Pin (4+4-Pin) CPU 12V Power Connector
• 1 x 6-Pin PCI Express Connector
• 1 x 8-Pin PCI Express Connector
• 6 x Peripheral Connectors
• 1 x 4-Pin Floppy Connector
• 6 x SATA Connectors

BFG LS550 features

• ATX12V 2.2 – Supports the latest Intel and AMD based platforms requiring 24-pin motherboard and 4-pin or 8-pin 12V connectors. The 20+4-pin motherboard connector also ensures backwards compatibility with previous ATX standards
• PCI Express® Ready – The PCI Express power connectors ensure compatibility with many high-end and several dual graphics card configurations without having to use unreliable, often performance hindering adapters
• SATA Connectors – Six serial ATA connectors allow you to connect up to six serial ATA devices without needing special adapters
• BFG Thermal Control Technology – During regular operation, the fan slows down to reduce unnecessary noise
• High Efficiency – While most computer power supplies pinnacle at 80% efficiency, the BFG LS Series is typically 80% to 85% efficient, which means more power drawn from the outlet is converted to DC power for your computer than many of the other units on the market

BFG LS 550 power supply photo gallery

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BFG EX-1200 specifications

• ATX12V 2.2/EPS12V 2.91
• Quad +12V Rails
• Silent 135mm Intake Fan
• Efficiency: > 80% Typical
• MTBF: > 100,000 Hours at 25°C, > 20,000 Hours at 40°C
• 1200W Continuous Rated at 40°C
• PCI Express Ready
• Dimensions: 15cm x 8.6cm x 16.5cm (5.9″ x 3.4″ x 6.5″)

EX-1200 DC Output

• +3.3V = 30A
• +5V = 30A
• +3.3V + 5V Max. Combined Wattage = 170W
• +12V1 = 40A
• +12V2 = 40A
• +12V3 = 40A
• +12V4 = 40A
• +12V Max. Combined Wattage = 1180W
• -12V = 0.5A
• +5VSB = 3.0A
• -12V + 5VSB Max. Combined Wattage = 20W

EX1200 power supply Box content

• 1 x 1200 Watt Power Supply Unit
• 7 x Modular Cables
• 1 x US Power Cable
• 1 x Users Guide
• 4 x Mounting Screws
• 5 x Velcro® straps

BFG EX 1200 Connectors

• 1 x 24-Pin (20+4-Pin) Motherboard Connector
• 1 x 4-Pin CPU 12V Power Connector
• 1 x 8-Pin CPU 12V Power Connector
• 1 x 8-pin (4+4) CPU 12V Power Connector
• 3 x 6-Pin PCI Express Connectors
• 3 x 8-Pin (6+2-pin) PCI Express Connectors
• 9 x 4-Pin Molex Connectors
• 2 x 4-Pin Floppy Connectors
• 12x SATA Connectors

EX1200 BFG power supply features

• ATX12V 2.2 / EPS12V 2.91 – Supports the latest Intel® and AMD® based platforms requiring 24-Pin motherboard and 4-Pin or 8-Pin 12V connectors. With the 20+4-Pin motherboard connector, it is also backward compatible with previous ATX standards.
• Quad +12V Rails – By splitting the +12V source into four separate rails, your components are provided the most stable power available while upholding rigorous safety standards.
• PCI Express® Ready – The PCI Express power connectors ensure compatibility with many high-end and graphics cards without having to use unreliable, often performance hindering adapters.
• SATA Connectors – Serial ATA connectors allow you to connect serial ATA devices without needing special adapters.
• BFG Thermal Control Technology – During regular operation, the fan slows down to reduce unnecessary noise.
• Protection Circuitry – Built-in protection circuitry is able to handle common power irregularities such as over-voltage, overload, and short circuits.
• High Efficiency – While most computer power supplies pinnacle at 80% efficiency, the BFG EX Series is typically 80% to 85% efficient, which means more power drawn from the outlet is converted to DC power for your computer than many of the other units on the market.

EX-1200 photo gallery

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