variable voltage adjustable power supply circuits

Features:
Regulated Adjustable Voltage out 2-30VDC
High Current Output 5A (based on transformer selection).
Adjustable Current Limit
Can be used as a variable current supply.
Based on LM317 Voltage Regulator.
Built in protection diodes
Speed controlled fan connection (based on current draw).
Current meter connection (0.1V/1A).

                                                           Circuit Diagram

Features universal capcitor mounting/spacing to allow various capacitors to fit.  Mounting pattern that fits TO-200 or TO-218/247 for pass transistor and transistor used for current limit circuit.  Fan connection uses connection compatible with standard PC fan connection; allowing use of PC heatsink fan combination.

Circuit Board Layout
Electronics Circuit Application 

MOBILE PHONE BATTERY CHARGER CIRCUITS.

Mobile phone chargers available in the market are quite expensive. The circuit presented here comes as a low-cost alternative to charge mobile telephones/battery packs with a rating of 7.2 volts, such as Nokia 6110/6150.