LM317 Power Supply Kit 101

Introduction

Welcome to the exciting world of Circuit Creations electronics kits. To assemble this kit you will need the following basic items:

·  25W to 40W soldering iron.

·  Rosin core flux solder.

·  Diagonal cutters.

·  Needle nose pliers.

The central component of this kit is the LM317 3-terminal positive adjustable voltage regulator. This device employs internal current limiting, thermal shut-down, and safe area compensation. The LM317 has proven itself over many years as an extremely versatile and robust device that has been used in a wide variety of applications. The Circuit Creations LM317 Power Supply Kit 101 uses a standard configuration for a well regulated, variable DC power supply. Your imagination is the limit for what can be done with this kit.

Circuit Assembly

The parts list for the components that are included with Kit 101 is as follows:

Designator / Value / Assembly Features
U1 / LM317 / Pay careful attention for installation of this component. The line on the PCB represents the side with the tab on the LM317.
B1 / DF005-G Bridge / Notch in package must match notch printed on the circuit board.
C1 / 100uF capacitor / Make sure + capacitor is the same as + on the circuit board.
C3 / 33uF capacitor / Make sure + capacitor is the same as + on the circuit board.
C2 / 10uF capacitor / Make sure + capacitor is the same as + on the circuit board.
R2 / 240 Ohm Resistor / Red-Yellow-Brown
R1 / 5.0K Potentiometer
D1, D2 / IN4001 Diode / Line on package must match up with line on the printed circuit board.
R3 / 1.5K Resistor / Brown-Green-Red
LED1 / LED / Flat side of LED and printed circuit board must match.
PCB1 / K101

The schematic shows the component connections. Be sure to pay attention to the markings on polarized components U1, B1, C1, C2, C3, D1, D2, and LED1.

See www.circuitcreations.com for general assembly helpful hints.

Operation

Note: Always exercise caution when connecting to power lines with an AC adapter.

Connect an AC adapter or DC voltage source such as a power supply or battery to VIN1 and VIN2 of J1. The input can be either DC voltage polarity (that is positive and negative input wires can be swapped) or an AC voltage since the bridge rectifier B1 will apply the correct DC polarity to the LM317. The input voltage must be at least 3 Volts greater than the desired output voltage (i.e. Vin – Vout > 3V) for the LM317 to provide proper regulation. The maximum input voltage for the Kit 101 circuit is 35 Volts.

The output voltage is available on J2 pins VOUT and GND and is adjustable by varying potentiometer R1. The LED will illuminate when the output is greater than approximately 2.5 Volts. The minimum output voltage is approximately 1.5 Volts.

For high power applications a heatsink (not included) may be needed for the LM317. See the LM317 data sheet at http://www.circuitcreations.com/Data_Sheets_And_Manuals.html for further information. ENJOY!!

Schematic

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