13.8V Power Supply | Electronic Project Circuits

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200 Watt Modified PC Power Supply 13.5 Volt 14 Amp

200 Watt Modified PC Power Supply 13.5 Volt 14 Amp
The external 230 Volt AC power ON/OFF switch is removed and bypassed.
Old unused outputs are removed. Over voltage protection changed to only protect one output at 16 V,
Voltage regulating resistor net changed to only monitor a single output,

Do it like this:
Cut: white, orange, blue, and yellow wires as close as possible to the pcb.
Cut: all plugs away in the other end of the black and red wires, parallel all red and black wires..
Desolder: Fan wires, L1, L3, L4, R25, R26, R27, R29, R50, R51, R52, R61, R66, D10, D16, D17, C29, C28, ZD1
Mount a 680 Ohm 1/4 Watt at R50 location.
Mount solderpins in the holes for R26, R61 and Fan connection.

Read More Source :http://www.webx.dk/oz2cpu/radios/psu-pc1.htm

Be the first to comment - What do you think? Posted by admin - October 19, 2007 at 9:13 am

Categories: Circuit com, Power supply, Switching power supply Tags: 13.8V power supply, Circuit com, High current power supply, Switching power supply

13.8V 10A Regulator by 7812 , 2N3055

The power supply circuit is shown in Figures 1 and 2. A 7812 positive 3-terminal regulator is used for the main 13.8V 10A regulator, and this is followed by as many power emitter followers as needed for the current you require. The transistors are not critical. I used 2N3771 devices (50V, 20A, 200W) simply because I had a whole bunch of them in my junk-box. These are pretty much ideal, but I suggest that you use whatever you can get cheaply. If you use 2N3055s (as indicated in the schematic), expect to use four transistors for the first 10A, and one transistor for each additional 5A peak (or 4A continuous) output capability to ensure an adequate safety margin. The voltage rating is unimportant, as the main supply will only be about 22V with an 18V transformer.

As you can see, the regulator is made adjustable over a small range, and will typically give from 11V to 13.8V at full load. With the no-load voltage set to 13.8V (nominal 12V battery voltage), the output will fall to 13.5V at about 1.5A, and 12.8V at around 13A. This is fairly typical of the voltage drops that can be expected in a car installation. Needless to say, if the supply is designed for more current, then the regulation will remain about the same, but at the higher design currents.

Source:http://sound.westhost.com/project77.htm
Thank you.

Be the first to comment - What do you think? Posted by admin - October 6, 2007 at 12:04 am

Categories: High current power supply Tags: 13.8V power supply, 2n3055, high current, LM7812

13.8V 20A Stabilized regulator by 7912,2N3055

This is circuit Power Supply regulator 13.8V 20A.
Use part Electronics IC 7912 and Transistor 2N3055 x 6.
It is High Current power supply and easy circuit.

The starting problem was to recycle some things: chassis, transfomer, heat sinks etc: what to do?
A power supply, of course !

This time I’ve stabilized the negative side using 6 cheap 2N3055 with collector directly mounted on the chassis.
TRANSFORMER
My transformer was 220/19V;
you can calculate the power it can give by the core dimension, but I’ve preferred use a practical way:
I’ve used a 100 meter / 1,5 mm wire and measured its resistance; it was about 1,1 ohm; so I’ve connected it to the output of the transformer; after about 30 seconds the transformer was still cold; well, due to the Ohm’s law, the trasformer was able to supply at least 19 / 1,1 = 15-18 ampere: OK, it was good.

RECTIFIER BRIDGE

Rectifier bridge’s diode usually see a voltage of Vout x 2,828, so it’s better to use one with a PIV 3 or 4 time bigger than the output voltage (19×3=57V);
same words for the current: a 50Ampere bridge has been used.
At first I’ve used a 25A one and infact after few test it has broken.

CAPACITOR FILTER

For a bridge rectifier you must use the following formula to calcule the amount of needed capacitance:

C= 1,8 x (I / VR)

where I is the max current and VR is the max ripple;
if a stabilizer follows the capacitors (as here), then you can use a value 40% lower than the calculated one; in my power supply I’ve used 2x 22000 microF / 40VL.
The working voltage of capacitor should be at least 40 % bigger than the output voltage.

STABILIZER IC
I’ve used a LM7912.
Read More Source:http://www.qsl.net/iz7ath/web/02_brew/20_ps7912/index.htm