Build Power Supply

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For this part of the build, you'll want to refer to sheet 1 of the v2.0 Schematic. You may also want to review the surface mount soldering tutorial. Click on any of the pictures below for a larger version of the picture.

Building and Testing the Power Supplies

Solder on C4, C5, and C13

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Solder input diodes D5 and D6

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Solder U1, 3.3V Regulator

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Solder U2, R27, J3

U2 is the 5 volt regulator. R27 is a 10 Ohm power resistor used to limit the power dissipated by the voltage regulators. J3 is the solar panel input header.

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Solder FB1, R9, R11, and D2

Solder in the ferrite bead, FB1. This connects the digital power supplies in with the switching power supply.

Go ahead and solder on the resistors R9 and R11 as well as the 3.3V LED D2. Do not install LED D1. There is a via under this part which will cause a short. This will be fixed in future versions of the board.


Test for Shorts

Using a multimeter in the ohm-meter setting, check the resistance across the terminals of J3, the solar panel input. The meter should read infinite or very large resistance after a few seconds. This is good. It means you didn't accidently short anything out!

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Apply Power

Apply power to the circuit via J3, the solar panel input. An adjustable voltage power supply is very useful here for monitoring both voltage and current. At this point the circuit shouldn't consume more than 10mA of current.

In lieu of a way to monitor current, feel the different parts with your fingertips to make sure nothing is getting warm. Pay particular attention to the voltage regulators U1 and U2. If anything is hot to the touch, disconnect power immediately! You have a short somewhere.

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Test for 5 Volts

Switch your multimeter into voltmeter mode. Connect the ground and touch the positive terminal of C17 to test for 5 volts.

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Test for 3.3 Volts

Touch the positive terminal of C6 to test for 3.3 volts.

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Congratulations! The 5 volt and 3.3 volt power supplies on your board are now working!