Arduino Power Supply v18.08
Contents
Design
Requirements
- Up to 300 mA supply (200 mA would likely be enough)
- 7-12 V DC output
- 120 V ac input
- Stable voltage reference of less than 5V (not needed if Arduino's internal reference is accurate enough, TBD)
Research
Non-isolated design could waste more power if Arduino is drawing less than the designed maximum output current. Isolated could lose a small amount of efficiency to transformer but would waste less power when the Arduino is drawing less than the designed maximum output current. For this application, isolated seems to be the way to go.
Power requirements for Arduino Mega (usually <70 mA, 200 mA max) and RepRap Discount Smart Controller (40-100 mA?). 300 mA max to power control and display circuits.
Drawing Power from Grid without Transformer for *Low Power* Applications
Precise voltage measurement with the Arduino
High Efficiency 400W AC/DC Power Supply Reference Design
Calculations
QUCS-S Simulation
Simulation providing 9V at >250mA
Electronics Design
These designs are not guaranteed to be safe or functional. Use at your own risk.
Prototyping
Successfully converted 120Vac to 10V at 380mA
Bill of Materials
Isolated
Fuse: FUSE GLASS 500MA 250VAC 5X20MM
Transformer: XFRMR LAMINATED 6VA THRU HOLE
Bridge rectifier: RECT BRIDGE 2A 40V 4SMDIP
Filter capacitor: CAP ALUM 680UF 10% 10V RADIAL
Output zener: DIODE ZENER 12V 5W AXIAL
Total cost of components ~$10
Non-isolated
Fuse: FUSE GLASS 500MA 250VAC 5X20MM
Cac: CAP FILM 10UF 5% 400VDC RADIAL
Cac discharge resistor: UPL1.064 RES SMD 1M OHM 1% 1/4W 1206
Bridge rectifier: RECT BRIDGE 2A 40V 4SMDIP or 4xUPL4.004 DIODE SCHOTTKY 40V 1A SOD123
Filter capacitor: CAP ALUM 680UF 10% 10V RADIAL
Output zener: DIODE ZENER 12V 5W AXIAL
Total cost of components ~$7
