Water Resistance Checker (basic) Model GSK-944 This checker utilizes resistance to measure dissolved solids in water. The more resistance, the less conductive the water Figure 1 Water Checker Circuit as resistance levels lessens the materials that conduct electricity are elevated. Results are displayed by a series of (8) LEDs. Technical Specifications n Power source: 9 VDC n LED resistance level indicators: 7 n LED on/off indicator: 1 n Level adjustment: 3 levels n PCB dimensions: 2.78 x 1.79 in. Operating Principles The more resistance in water the less dissolved solids, such as minerals, are present. Conversely, as resistance decreases the level of conductive material in the water increases. A series of (green, yellow, and red) LEDs indicate the level of resistance (Green higher through Red lowest) the more LEDs lit the less resistance. There are 3 switchable levels (see Figure 1 resistance table). 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 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 the battery to provide power to the circuit. The LED power light will come on. Slide switch SW to position 1. Insert probe into water source, LED 1 through LED 8 will display level of resistance in water source. Troubleshooting Accessories The main cause of problems will come from misplaced Use GSB-03 (sold separately) to house the PCB and batteries. components or faulty soldering. Utilize Figures 1, 2 and 3 to ensure proper placement, polarity and then check solder points for connectivity. Electronic Kit Set for Hobby & EducationFigure 2 Connecting Circuits Figure 3 Installing components GSK-944 Resistors R1, 30 1 k brown black red gold R2, R8, R11, R14, R17, R20, R23, R26 10 k brown black orange gold R3 100 k brown black orange gold R4, R6, R9, R12, R15, R18, R21, R24, R27 1 M brown black green gold R5, R28 20 k red black orange gold R7, R19, R13, R16, R19, R22, R25, R28 5 k green black red gold R31 3 k orange black red gold Electrolytic Capacitors C1, C2 33 F Diode ZD1 5.1 V Integrated Circuits IC1, IC2 LM339 Switch Position 1 Position 2 Position 3 LED Water Resistance LED Water Resistance LED Water Resistance 8 0.98 k 8 18.83 k 8 197.26 k 7 2.48 k 7 33.80 k 7 347.04 k 6 4.41 k 6 53.06 k 6 539.62 k 5 6.97 k 5 78.74 k 5 796.39 k 4 10.57 k 4 114.61 k 4 1,155.86 k 3 15.96 k 3 168.61 k 3 1,695.08 k 2 258.48 k 2 2,593.77 k 1 438.22 k 1 4,391.16 k www.globalspecialties.com