Abra AK-252 User manual

Variable Power Supply
1.24VDC - 26VDC Educational
DIY KIT for Breadboard
Variable Power Supply
1.24VDC - 26VDC Educational
DIY KIT for Breadboard

1
Table of Contents
Components List.............................. 2
Tools required .................................. 3
Special Features of AK-252............. 3
Assembly .......................................... 4
Let’s Get Start with Soldering......... 4
How To Use....................................... 8
Schematic ......................................... 9
Board Layout .................................... 9

2
Components List
QTY Description Abra Part #
1 PCB Board AK-252-BRD
1 MIC2941-Voltage Regulator IC MIC2941ABT
1 1N5818 Diode 1N5818
2 1K-Resistors R1/4-1K
1 Resistors: 11K
20K
6.2K
R1/4-11K
R1/4-20K
R1/4-6.2K
12.1mm Power Jack 31-155-0
1 100K Potentiometer 13P100K
2Capacitors: 104uf
47uf
CM104
47R25
1Switch SSW-120-BB
1 3mm pitch Terminal Block 2444P-1
1 Male Header SH-2
1 Heat Sink 574502B00000G
1 3 Way SP3T switch OS103011MS8QP1
2 3mm LED (one Green, one Red) LED-3R, LED-3G

3
Tools required
Special Features of AK-252
This Breadboard power supply module is designed to get regulated voltage
from any external power source, either from the DC barrel jack or terminal
block. The best part of this board is, you can use the power supply at three
di󰀨erent modes of voltages- 3.3V,5V and at variable voltages from 1.25V to
20V. The end user can select the voltage using 3-way switch.
Features:
• Used MIC2941 which has low voltage dropout (40mV) comparted to
LM317(1.25V).
• 2.1mm DC jack and terminal connector for voltage inputs.
• Two indicator LEDs, Red for input power and green for output power.
• Short circuit and over heating protection.
• Input diode to protect circuitry from negative voltages or AC power
supplies
• Onboard potentiometer for adjusting voltage from 1.25V to 20V with in
0.5V of the input voltage.

4
Assembly
Let’s Get Start with Soldering
Follow my step by step instructions
below to solder the PCB board. Carefully
observe the note points that are provided.
Step 1:
Start with IC, place as shown.
Note: Keep a little up for bending.

5
Step 2:
Follow up by 2.1mm power jack.
Solder it by placing board to the
support as shown
Solder the two types of switches
to there respective places.
Three pin switch is on-o󰀨 switch
and sw2 i.e. bigger switch is an
output voltage adjustable switch.
Step 3:
In this step you will solder the capacitors and the LEDs.
The Red LED is put into LED1 and Green LED is put into LED2. The red
indicates whether the board has input power. If red LED glows that means
your board is connected to the input. To get output, you need to switch
on the switch rst. Then green LED glows according to the voltage you
choose.
• Check polarity of the capacitor.
• Long one represents positive.
• Solder all the capacitors to there
respective positions.
• Check the polarity of the LED and
solder according to it
• Bigger terminal indicates positive
and smaller is negative.

6
Step 4:
For this step solder the potentiometer and diode as indicated in the picture
below. Make sure the direction of the diode is same as per the PCB.
Note: the silver coting of the diode is the n-side i.e. point your silver side
towards the arrow symbol of the diode as shown in gure.
Step 5:
Now the most important thing to do is solder the headers.
These are very sensitive as the orientation to the breadboard may disturb.
Follow the tips shown in below.
First place all the headers on the breadboard, then place the PCB upon it
and solder.
• Place headers to the breadboard as shown.
• Place slowly the PCB on the headers.
• Make sure all the headers are inserted
• Solder it as shown in gure.

7
Step 6:
Finally, you will solder all resistors and the terminal block.
• R1: 1K • R2: 1K • R3: 20K • R4: 11K • R5: 6.2K

8
How To Use
The Power Supply Provides three di󰀨erent output voltages. The voltage
can be set to 3.3V and 5V or it can be adjusted using the potentiometer
from 1 to 20V. The Red LED indicates whether the board is getting power
or not. The Green LED indicates that the power supply is providing an
output to the “JP1” header. The Brightness of this LED can increase or
decrease on the voltage at this header.
In order to turn the power supply on/o󰀨, the ON-OFF switch is used.
The SW2 switch is used for the output voltage adjustment.
Note: If IC gets heated, keep heatsink on it.

9
Schematic
Board Layout