5V/3.3VブレッドボードDC-DC電源


5V/3.3VブレッドボードDC-DC電源

Assembly Instructions

The 5V/3.3V Breadboard DC-DC Power Supply comes as a kit, and must be assembled before use. It consists entirely of easy to solder Through-the-hole components, and can be assembled by anyone with basic soldering experience.

Requirements

To solder this kit, you will need:

  • A soldering iron
  • Solder
  • A wire cutter (a diagonal type that allows you to cut the wires as close to the soldering points as possible is best)
  • A multimeter
  • A breadboard

Optional:

  • Helping hands or a vise to hold the PCB in place when soldering
  • Tweezers to help pull the legs of the components through the holes (an angled tweezer is ideal for this)
  • Desoldering wick
  • Solder sucker
  • Protective glasses

See the equipment page for more details.

Step 1

The first step is to place the four small 1/6W resistors. You can place all of them at once, or one at a time, depending on your preference.

It is very important that the correct valued resistors are inserted into the proper holes, otherwise the power supply will not work properly.

The values are as follows:

  • R1 30kΩ (orange, black, orange, gold)
  • R2 10kΩ (brown, black, orange, gold)
  • R3 18kΩ (brown, gray, orange, gold)
  • R5: 1kΩ (brown, black, red, gold)

The marking on resistors can sometimes be diffiult to read. It is best to use a multimeter to double-check the values of all the resistors before insertion. Resistors are not polarized and can go in any way.

Bend the legs of each of the resistors out on the back side of the board, and then turn it over. Now carefully solder each of the points.

Next, use a flat wire clipper to trim off the excess part of the legs:

Step 2

The next step is to place the two diodes. Again, it is very important that the diodes go to the correct places. Also, diodes are polarized and must go in the correct way.

The two diodes are 1N4001 and 1N5819. The number is written on each diode, but otherwise they are identical in appearance. 1N4001 goes in the upper right, next to the 1kΩ resistor. 1N5819 goes on the left side, next to L1.

Diodes must be inserted so that orientation of the white band on the diode matches the band drawn on the footprint on the PCB.

The diodes have quite thick legs and can be a bit difficult to push together. You may want to use pinchers to pull the legs to align the diodes flat against the PCB.

Step 3

Next, find the two small ceramic capacitors. One is blue, this is the 0.1µF capacitor that goes to the left of the resistor footprint marked R4. The other one is yellow, it is a 470pF capacitor, and goes into the hole marked C4.

Ceramic capacitors are not polarized and can go in any way.

The 470pF capacitor and PTC fuse look similar: Be sure to chose the right one: The capacitor is the smallest one.

Step 4

Next, let us place the MC34063A chip. It goes into the 8-pin footprint in the middle of the board. Place it so that the circular dot on the side of the chip goes to the left, facing the half-circle drawn on the PCB.

When you turn the board over to solder this part, it may fall out. You can use clips or a piece of masking tape to hold it in place while soldering. First solder only one leg, then check that alignment is good, and that the chip lies paralell to the PCB. If alignment is bad, re-apply heat and adjust. Once you are happy with alignment, solder the remaining 7 legs.

Step 5

Locate the final 0.15Ω or 0.16Ω resistor. It goes in the footprint marked R4. It is bigger than the fooprint and must be inserted at an angle.

Also insert the PTC fuse, it goes right under the 1kΩ resistor. It is not polarized and can go in any way.

Step 6

Next, let us place the electrolytic capacitors and the LED. These are all polarized. The long leg is +, and should go into the square hole in the corresponding footprint.

  • The brown 47µF or 33µF capacitor goes to C2
  • The brown 330µF capacitor goes to C3
  • The LED goes in the footprint marked PWR.

Step 7

Next is the inductor. It is the long cylinder. Place it in L1. Polarity does not matter.

Step 8

Place the 3-pin male header in the holes on the right side of the board (marked 5V/3.3V). It may fall out when you turn the board over, so use clips or a piece of masking tape to hold it in place. Solder one leg first, and make sure aligment is proper before continuing.

Now place the 2.1mm power jack plug. Again, you can use masking tape to hold it down. Solder one leg first and check alignment before proceeding.

WARNING: This part will get very warm when soldering it. Let the board cool down a little before proceeding.

Step 9

Place the 2x3 male header into the power rail of a breadboard as shown in the picture. The long legs should go down into the breadboard.

Step 10

First, insert the jumper in the 5V/3.3V selector: It goes over the bottom two pins for 5V or the top two pins for 3.3V.

Next, place the board over the 2x3 pin connector in the breadboard. Solder one pin first while holding or propping up the board. Make sure the alignment is good before soldering the remaining pins.

Congratulations! The 5V/3.3V DC-DC power supply is not assembled and ready for use.

Head on to the Usage page for further instructions!