This will show
- How to make a Molex 4 Pin Power Supply from a Conventional 12V Adapter?
- Run 2 External Hard drives with one Power Adapter.
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Step 1: Parts Needed
Most of the parts from scrap which is shown.
- 12V 2A Adaptor
- Male Power Connector (which suits the External HDD)
- Female Power Connector (which suits the Power Adapter 12V 2A)
- LM7805 IC
- 100 uF 25V Electrolytic Capacitor
- 0.1 uF Capacitor, Code - 104
- 3.3K Ohms Resistor
- 3mm Green or Blue LED
- Male 4 pin Molex Connector
- 7805 PCB or just use a scrap Terminal Connector as used for testing only
- Heat sink (HIGHLY RECOMMENDED)
It is highly preferable to mount the circuit in a proper PCB. Since 7805 dissipates large amount of heat even for a short time. It is highly recommended to add a powerful Heat Sink for a long run.
Step 2: Circuiting
Mostly pictures and self explanatory
Make LM7805 Circuit in a PCB and provide a Heatsink
12V 2A Output to Female Connector
Female Connector for Molex 12V and GND
Female Connector to Male Connector for Pwr supply other HDD
Circuit the LM7805 IC as shown and take GND and +5V to Molex
Connect +12V GND GND +5V as per the pinouts shown
Step 3: Testing
Totally self explanatory check the attached picture.
Check quoted notes in the picture.
Step 4: Output
Picture showing both HDD powered with a single 12V adaptor.
Finish the tested circuit in a PCB and a proper Enclosure.