2-7V / 6-8A Power Supply by 723 and 7812

Description: 

In this 2-7V power supply circuit, for our purpose, we chose IC 723 instead of a three pin voltage regulator for-why we find it protean and more advantageous in technical details.

Notes: 

Heatsinks of Tr2 and Tr3 transistors must be sufficiently large.

To archive R4,R5 and R6 values, we used some suitable resistors in parallel. For R4 and R5 two parallel connected 0.3ohm/5W resistors for each are used. To take 6A output, we connected two 0.22ohm/5W resistors in parallel, and to take 8A output we connected three 0.33ohm/5W resistors in parallel instead of R6 resistor. 

If you change the marked component values properly you can get up to 14V output. For this situation you must disconnect R1,R2,C5,C6,C1,C2,D1,D2  components and connect the positive terminal of D3 directly to the rectified and stabilized supply....

General Purpose Power Supply by L146 or IC 723

Description:

This power supply is designed for general purpose use. Advantages of the circuit are first the voltage can be adjusted from 0V to greater and second it does not require a double sided secondary winding transformer.

For high voltage outputs you can use L146 or alternatively if you need lower voltage outputs you can use IC 723.  Although output current limit is variable, it will be fixed after adjusted. In the table,  suitable component values are listed for three different cases (max. outputs: 30V, 40V and 60V). In the schematic 40V/0.8A example is shown.

The reason why L146 is used in the schematic is higherslew rate than the IC 723.

Regulation voltage for both integrated circuit is at least 2V. R3, R4, R5 and R6 resistors prevent this limitation and keep the output voltage at 0 level with the help of P2 potentiometer. If the input voltage is less than required, this resistors provides sufficient potential between 4 and 5 numbered pins...

1.2 - 12V / 1A Low Voltage LED Indicator Power Supply by LM317

Description:

This is a 1.2 - 12 V, max 1A power supply with a low voltage indicator LED. The indicator part includes three diodes and one LED. For example you are charging a battery, you can observe the charge status at that moment. Another advantage of this circuit, when the drawn current exceeds 1A (practically 0.85A), the current protector in LM317 intervenes and LED indicator warns you about the very low output voltage.

Be careful while choosing the transformer. Most of the products are specified as 10VA but their outputs are not as said.

Another good property of this circuit is the mains noise does not pass to the DC part.