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.

d2 Hard Drive LaCie Power Supply Specs

• Item Number : 800040
• Power :
  • DC Output: 12V (3A) / 5V (4.2A): 57W
  • AC Input: 110V / 220V
• For Use With These Products : LaCie d2 Hard Drive

IMPORTANT NOTE: You must only operate your drive using the corresponding d2 HardDrive power supply stated above. Using a power supply that was not intended for use with your drive could result in damage to the device and will void your warranty.

Computer power supply specs

Computer power supplies are rated based on their maximum output power. Typical power ranges are from 300 W to 500 W . Power supplies used by gamimg solutions sometimes range from 500 W to 1300 W. A common way to reach the power figure for PC PSUs is by adding the power available on each rail, which will not give a true power figure. This means that you cannot use the PSU maximum rating on one rail, but only as a total. Therefore you can overload a PSU on one rail without having to use the maximum rated power.

Computer power supply pins

1. PC Main power connector: Is the connector that goes to the motherboard to provide it with power. The connector has 20 or 24 pins. In cases where the motherboard has a 24-pin connector, some power supplies come with two connectors (one with 20-pin and other with 4-pin) which can be used together to form the 24-pin connector.
2. ATX12V 4-pin power connector. A second connector that goes to the motherboard (in addition to the main 24-pin connector) to supply dedicated power for the processor. For high-end motherboards and processors, more power is required, therefore EPS12V has an 8 pin connector.
3. 4-pin Peripheral power connectors (Molex): These are the other, smaller connectors that go to the various disk drives of the computer. Most of them have four wires: two black, one red, and one yellow. Unlike the standard mains electrical wire color-coding, each black wire is a ground, the red wire is +5 V, and the yellow wire is +12 V.
4. Serial ATA power connectors: a 5-pin connector for components which use SATA power plugs. This connector supplies power at three different voltages: +3.3, +5, and +12 volts.
5. 6-pin Most modern computer power supplies include 6-pin connectors which are generally used for PCI Express graphics cards, but a newly introduced 8-pin connector should be seen on the latest model power supplies. Each PCI Express 6-pin connector can output a maximum of 75 W.

Efficiency of the computer power supply

Computer power supplies efficiency is generally about 70–75% efficient. That means in order for a 75% efficient power supply to produce 75 W of DC output it would require 100 W of AC input and dissipate the remaining 25 W in heat. Higher-quality power supplies can be over 80% efficient; higher energy efficient PSU’s waste less energy in heat, and requires less airflow to cool, and as a result will be much quieter. As of 2007, 93%-efficient power supplies are available.

For more information visit en.wikipedia.org/wiki/Computer_power_supply

d2 Blu-ray & DVD +/- RW v.1 LaCie Power Supply

• Item Number : 800040
• Power : 34W
• For Use With These Products :
  • LaCie d2 Blu-ray drive v1
  • LaCie d2 DVD +/- RW drive v1

IMPORTANT NOTE: You must only operate your drive using the corresponding d2 Blu-ray & DVD +/- RW v.1 power supply stated above. Using a power supply that was not intended for use with your drive could result in damage to the device and will void your warranty.

The L165 IC can also be viewed as a voltage amplifier. It amplifies the voltage appearing at the junction between R1 and R2.
One cas also replace the IC with TCA1365. However, when using the TCA IC, pins 3 and 4 have to be connected together. Also connect a 220pF capacitor between pins 5 and 6.

Symmetrical power supply schematic

Symmetrical supply printed circuit layout

This has the advantage that only low-value inductor and capacitors are needed, and this results in excellent efficiency and small dimensions. In normal circumstances, the efficiency is 90% and may even go up to 96%. Both ICs provide protection against current and temperature overloads.

The LM2671 has a number of additional facilities such as soft start and the option to work with an external clock. The latter enables several supplies to be synchronized so as to give better control of any EMC (ElectroMagnetic Compatibility). The application shown in the diagram provides an output voltage of 5 V and an output current of up to 500 mA. Diode D1 is a Schottky type ((Uco≥ 45 V and Imax≥ 3 A).

A core should be chosen to work within the specific frequency as stated by the manufacturer. L1 is a powder core and has 32 turns of 0.75mm wire.

Variable Power Supply Circuit Diagram

The transformer has a 240V primary and has a secondary rated 24V at 2A. The bridge rectifier contains 4 diodes, their current rating needs to be high with respect to the transformers output current; if not the current may damage the diodes. C1 is the mainfiltering capacitor, the supply is further smoothed by the combination of L1 and C3. C2 and C4 are decoupling capacitors; their action further reduce ripple factor.

The regulator 78xxr, U1 utilizes the action of zener diode ZD1 which is in parallel with the potentiometer, R1. The tuning action of R1 produces a variable regulator output. The output voltage is variable from the regulator output to the regulator output plus the zener voltage. E.G. A 7805 regulator and 10V zener give an output adjustable from 5 to 15 Volts. The regulator may be changed to provide different output voltages as may the zener. the zener should be rated a minimum of 1.3 Watts.

T1 Transformer 10:1 Secondary 24V @ 2A
BR1 Bridge Rectifier 50V PIV 2A rating
U1 7805 N.B. This may be changed for different output voltages e.g. 7812 for higher output voltage
ZD1 15V zener @ 1.3W

Source:http://www.zen22142.zen.co.uk/Circuits/Power/vpsu.htm

The variable power supply circuit presented here is designed to give maximum voltage level of 28 volts. If P1 is replaced with 25K potentiometer, the regulator can deliver up to a maximum of 30 volts. Capacitors C1 and C2 stabilize the IC and they must be connected as close as possible to the IC terminals.

The IC UA79G delivers negative voltage level. Take note that the two ICs have different terminal connections.

UA78G/UA79G power supply circuit diagram

Variable power supply PCB layout

3 volts car adapter circuit schematic

The circuit is connected to the car +12-V system via the cigarette lighter socket — is advisable to use a fused version of the cigarette lighter plug. The +12-V arrives on the board via screw- terminal block J2. Diode D2 provides a reverse voltage protection, while C3 decouples the input to the switcher IC.

The LT1074CT briskly switches the supply voltage on and off in response to the signal applied to its F/B input, to the extent that the average output voltage is at the required level. The values of potential divider resistors R1-R3 have been chosen to attenuate the output voltage so that there is 2.5 V at the F/B pin. The difference between the attenuated output voltage and the internal 2.5-V reference is used to control the modulation effect of the switcher.

Components R2 and C2 provide frequency stabilisation for the feedback loop. Inductor L1 along with the LT1074CT form the main switching components, while C1 provides decoupling for the output load. The 3-V output voltage is taken from screw terminal J1. With this circuit built, boxed up and installed in your car, you can look forward to possibly your first ‘quiet’ long car journey.

Network Space | Internet Space LaCie Power Supply Specs

• Item Number : 800053
• Power : 36W(12V)
• For Use With These Products :
  • LaCie Network Space
  • LaCie Internet Space

IMPORTANT NOTE: You must only operate your drive using the corresponding Network Space | Internet Space power supply stated above. Using a power supply that was not intended for use with your drive could result in damage to the device and will void your warranty.