Microprocessor power supply circuit, 5V 3A by LM323K

Those who want to have the Microprocessor power supply circuit, for use in experiments such as logic circuit and/or the Microprocessor types that use voltage size 5 volt And the amount of current consumption very much. This circuit will respond your needs did well
– Due to this circuit is very simple with the IC-LM323K (or LM123 or LM223) only one. But the can supply 5V fixed output voltage, and can be connected load current up to 3 Amp.

(If you not can buy this IC or want easy circuit with more transistor please read down)

How it works.
As shown in circuit Figure 1, will seen that the IC LM323K, only one.
can buy it at

In the circuit is made up of only a few pieces of equipment, such as
-The transformer acts to reduce the voltage from AC 220V to AC 9V.
-The bridge diode of size 4 Amp, is converted AC voltage into a DC voltage. Which we have C1 is the current filter smoothly
-Then IC1-LM323K is used to
It is used to maintain a constant voltage 5V. In addition, the internal circuit overload protection. Due to Short Circuit output and the thermal protection system over determine as well.
– C2 is noise frequency filter.
– C3 is the output filter.

Figure 1 The circuit

Figure 2 the PCB laout.

The parts
C1__________________1000uF 16V Electrolytic capacitor
C2__________________0.1uF 63V Polyester Capacitor
C3__________________470uF 16V Electrolytic capacitor
T1__________________Transformer out 9V at 3A.
BD1_________________Bridge diode 4A 200V.

All equipment according to the circuit. Except the transformer can be mounted on the PCB is shown in Figure 2. In installing the IC1, be careful not to input or an output short circuit with the heat sink is strictly prohibited.
Note: Please see datasheet of LM323K before make this project.


+++ The other way of 5V 3A power supply for digital circuit!


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  1. Joe September 28, 2012
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