Sunday, 22 September 2013

Power Supply

To make my Armdroid as portable as possible, decided it would be sensible to make up a dedicated Power Adapter instead of relying on my Bench Power Supply....

I bought a slimline AC Adapter with a regulated rated output of  12V, 5.0A from CPC - I think costing around £17 + VAT.   I could have chosen a 4 Amp adapter, but oddly, was more expensive.

I cut off the 2-pin connector and soldered on the GX-16 style connector, making sure the pins have the correct polarity:



On my Armdroid, +Vcc is on right hand side, GND left, as the connector is viewed plugged in.  Yours might be different, so it's worth double checking by following the cabling in the base to the 7805 power voltage regulator to determine polarity.   The 7805 has the following pin-outs:


The regulator on my Armdroid is bolted to the chassis, yours might be mounted directly on the PCB, but you can identify the +12V /+15V line by tracing the cable to the Input pin.  A multimeter can help with this.



The completed power supply :