Circuit Project Electronic

Here is circuit 8V 1A Switching power supply, Use IC LM2575.
Input Volt 10V-40V DC only.
This Citcuit to become for Car or motorcycle,Use Volt 12V-14.4V 2A.
And Volt Output 2.3V-37V change by R1,R2
Detail see in image circuit and PCB.
Related Links
More circuit about switching power supply
More circuit by IC LM2575
LM2575 Switching Regulator 1.2-12V for [...]

The LM2575 works a regulator only and don’t deliver any current to the load.
If the regulator switches “ON”, you find a voltage at the output of it. This makes T4 switching on also.
The collector of T4 now is nearly GND and also the Gate of FET T3. This FET switches on (it’s a P-FET!)
For T3 [...]

This circuit is derived from an application note of LM2575, It is a Power Switching Regulator from National Semiconductor.
National Semiconductor The details are here
LM2575
An application note by On Semiconductor shows how this chip can be used to generate Negative Voltage Power Supplies from Positive Voltages.
A Power Transistor which is having a drop of 4 [...]