LED Adjustable Speed Flasher Model GSK-109 This is an excellent kit for introducing basic electronic principles. Figure 1 Installing components Two LEDs will alternatively blink and the blinking speed is adjustable. Kit is easy to assemble with minimal components. Technical Specifications n Power Source: 9-12 VDC n Consumption: 16-22 mA max. n Adjust flashing speed with potentiometer n PCB dimensions: 1.39 x 1.22 inches Operating Principles This is a two LED circuit that works alternatively through transistor 1 and transistor 2 in the form of a multi-vibrator frequency circuit. When TR1 is powered, LED1 will light and LED2 is off. When TR2 is powered, LED2 will light and LED1 is off. Blinking speed is controlled by potentiometer VR1. Circuit Assembly Please refer to Figures 1, 2, and 3 for aid in component placement. It is recommended to start with lower components i.e. diodes, resisters, electrolyte capacitors, and transistors. Be careful to check polarity with Figure 3 before soldering. If a problem is detected it is best too use a desoldering pump or desoldering braids to remove component. This will minimize potential damage to the printed circuit board. Testing Connect circuit to 9-12 VDC power source. LED1 and LED2 will work alternatively. Adjust blinking speed with VR1. If LEDs do not light or blinking speed will not vary please review Troubleshooting. Troubleshooting This circuit has only a few components. The main cause of problems come from misplaced components or faulty soldering. Utilize Figure 3 to ensure proper placement/polarity and then check solder points for connectivity. Accessories Use GSB-17 (sold separately) to house the PCB and batteries. 22820 Savi Ranch Pkwy, Yorba Linda, CA 92887 Toll Free: 800-572-1028 www.globalspecialties.comFigure 2 LED flasher 2 dot circuit Figure 3 Connecting circuits GSK-109 Resistors R1, R4 470 yellow violet brown gold R2, R3 3 k orange orange red gold Potentiometer VR1 10 k or 103 Electrolytic Capacitors C1, C2 33 F Transistors TR1, TR2 C458, C828, C945, C1815 www.globalspecialties.com