This project is suitable for beginners. Some soldering tools are necessary but even if you've never soldered before this will not be that difficult. You can buy this kit from the Purple Squirrel website or you can gather the parts your self and using the Eagle files from the website get your own PCB(s) made and go that route.
Step 1: Getting Started
Your parts list (if you bought this from Purple Squirrel) should include these 16 pieces:
(1) LM317 Voltage Regulator
(2) SPDT Slide Switches
(2) 0.1” Header Pins
(1) 100uF 25V Aluminum Electrolytic Capacitor
(1) 10uF 25V Electrolytic Capacitor
(1) 0.1uF 50V Ceramic Capacitor
(1) PTC resettable fuse
(1) LED, Red
(1) 390 ohm resistor
(2) 330 ohm resistors
(1) 240 ohm resistor
(1) 1N5818 Reverse Protection Diode
Step 2: Assembling the Kit
Start with the PCB
Step 3: Installing the Resistors
You may need to pre bend the leads like the picture to get the parts to fit.
Once the resistor is in the location turn the PCB over and bend the leads a bit as shown…this will hold the part in place while you solder it down.
After soldering the leads down, trim them off so they look something like the picture.
Repeat the above steps for the remaining resistors (390 ohm and the 240 ohm).
Step 4: Installing the SPDT Slide Switches
Because the leads don’t bend I put them in to their positions first and then turned the whole assembly over and let the PCB rest on the switches and then soldered the leads down.
Step 5: Installing the LED
Step 6: Installing the Capacitors
Install the 10uF capacitor as you did the 100uF one. The 10uF capacitor has the markings “25V 10uF” on the side. You will also see the same marking indicating the negative side of the capacitor along with the negative lead being shorter.
The 0.1uF capacitor is the smallest capacitor of the three as well as the smallest part in the kit. This type of capacitor is not polarized as it is a ceramic type of device and as such can be installed without any concerns regarding polarity as shown in the pictures.
Step 7: Installing the Diode
Like the resistors and other parts bend the leads a bit to hold the diode in place for soldering and then trim the excess away.
Step 8: Intalling the PTC Resettable Fuse
Install the PTC into its position and gently bend the leads to hold in place and solder it in. Once soldered, trim the excess away.
Step 9: The DC Connector Jack
Step 10: Installing the 0.1” Spaced Headers
I installed these into the PCB from underneath and let the PCB rest on the headers. This allowed me to solder the pins from the top side of the PCB.
Step 11: Installing the LM317 Voltage Regulator
When it is all said and done your power supply kit should look like this when you are finished.
Step 12: Lets Test the Kit :-)
Once its plugged we switch the ON/OFF switch to ON and you should see the LED light up. I set the voltage selection to 3.3V.
Put the probes on the Vout pins and we see….3.29V.
Now we switch the voltage selection switch to 5V.
Put the probes on the Vout pins and we see…5.02V
There you have it, a fully functional power supply that will give you 3.3V and 5V and up to 500mA of current.