SINGLE FLASHING LED

INSTRUCTION SHEET

 

 

 

 

Price - Stock No 80

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Schematic Diagram

 

PCB Layout

 

 

  1.  Turn the PCBoard over so that you are looking at the PLAIN side. From the drawing, find the locations of the components. You will need to turn the PCB around so that it coincides with the placement sheet. Remember that you are seeing the copper track through the PCB.
  2.  Identify the values of the three resistors by their colour bands and/or an ohm-meter. Bend the legs of the resistors to a shape that will fit into their location holes. Push them through and firm the resistor down against the PCB.
  3. The two transistors look the same but are really quite different. Look for the identifying codes on the body of the transistors. Offer the transistors into their positions with the flat on the body the way round that the drawing indicates. Bend the legs to fit into the holes. Push them in, but allow to stand high off the board.
  4. Spread the legs of the LED carefully so they spring into its correct holes. Push the legs just through the PCB so the LED stands high off the board. You should check that the small flat on the flange at the base of the globe is the same way round as the drawing shows. The LED is polarised - a semiconductor - and will not work if placed the wrong way round. The flat is adjacent to the Negative (K) leg.
  5.  The electrolytic capacitor is polarised. An arrow is printed on the body pointing down the negative leg. Check the placement sheet for its polarity and location, push the legs through and solder.
  6. The disc ceramic capacitor is not polarised so it can go in either way. Notice that the value of this capacitor is coded on its surface. This one reads 103. The first and second numbers are value digits and the third (3 in this case) is a multiplier, viz. indicates the number of zeros following. This shows a value of 10000 -(1 + 0 + 000). This value is always expressed in picafarads. Reference to a table will show that this converts to 10 nanofarads, or 0.01 uF.
  7. These components may be soldered in place.
  8. Insert and solder the PCB pins.
  9. The battery snap is sildered with the red wire to the positive rail, black to the negative rail.
  10. Connect a battery and the flasher will commence. The current draw is very small and the voltage is not critical, so the light will flash for a very long time from the battery even when the battery is almost completely flat. 
  11. Trouble shooting will consist of checking locations, polarity, and soldering. 

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