Mosquito Repellent Model GSK-918 This circuit generates a frequency 10-30 kHz that creates a sonic zone disturbing to mosquitoes. A piezo board creates the Figure 1 Installing components frequency equal to the frequency generated by the mosquito during flight causing the mosquito to believe he/she is flying into a trap. Technical Specifications n Power Source: 3 VDC n Power consumption: 20 mA max. n PCB dimensions: 1.60 x 1.39 inches Operating Principles Transistor 1 and 2 control low frequency 10 kHz, while transistors 3 and 4 control high frequency 30 kHz. This circuit is designed to alternate the frequency and transmit the sound through the piezo board. PCB 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. Take extra precaution to ensure electrolytic capacitors are inserted correctly. 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 the piezo board at PZ point on PCB. Apply power source and turn potentiometer VR1, a sharp sound should be omitted from the piezo board. Troubleshooting The main cause of problems will come from misplaced components or faulty soldering. Utilize figure 2 and 3 to ensure proper placement, polarity and then check solder points for connectivity. Accessories Use GSB-03 (sold separately) to house the PCB and batteries. Electronic Kit Set for Hobby & EducationFigure 2 Mosquito Repellent Circuit Figure 3 Connecting Circuits GSK-918 Resistors R1, R4 100 brown black brown gold R2, R3 12 k brown red orange gold R5, R8 330 orange orange brown gold R6, R7 3.9 k orange white red gold Potentiometer VR1 - 14 or 103 or 10 k Electrolytic Capacitors C1, C2 - 33 F C3 - 10 F Ceramic Capacitors C4, C5 - 103 or 0.01 F Transistors TR1 TR4 - C458, C828, C945, C1815 Diode D1 - 1N4148 www.globalspecialties.com