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Defibrillator Tester Construction Manual
Defibrillator tester kit items:
Printed Circuit Board (1)
Striped Resistor (1)
White Capacitor (1)
Red Light Emitting Diodes (LEDs) (2)
Black and silver Diode (1)
Orange and black Zener Diode (1)
12-inch piece of wire (1)
Adhesive pad (1)
Black box with four screws (1)
Foil tape pieces (2)
Necessary Tools:
Needle nose plier
Wire stripper/cutter
Soldering iron
Solder
Heat sink
1
Striped Resistor
Printed Circuit Board (PCB)
Black and
silver diode
Orange and black White
zener diode capacitor
with black
stripe
Red Light
Emitting
Diodes
Figure 1. Electronic components for building the circuit board
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Building the Circuit on the Printed Circuit Board (PCB)
Step 1
Identify the orange and black Zener diode, which is to be placed over the spot marked ‘Z1’ on the PCB.
Bend the leads and insert them into the holes on either ends of the spot marked ‘Z1’, making sure that
the black band on the diode is facing the top edge of the board (Figure 2).
Insert the diode leads such that black stripe is
facing the top edge of the board (like the stripe
painted on the board). Pull the diode through
so that it sits flush against the board. This
diode is inserted only half-way!
Figure 2. Placement of the orange and black Zener diode onto the PCB
Pull the diode leads through the holes until the diode sits securely on top of the board. Attach a heat
sink onto the diode’s lead on the front side of the board. This protects the diode from the heat of the
soldering iron.
Soldering Instructions:
Flip the board onto its back side. Using a soldering iron, heat one of the leads until solder placed on it
melts. Using this technique, solder both leads onto the board, making sure that there is a good
electrical and mechanical connection. Cut any extra lead protruding above the solder mound. Figure 3
shows what the backside of the board should look like after the soldering is completed.
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Solder Mounds
Figure 3. The backside of the PCB after the orange and black Zener diode has been soldered onto it
Step 2
Black and silver diode placement: Identify the black and silver diode, which is to be placed over the spot
marked ‘D1’ on the PCB. Bend the leads and insert them into the holes on either ends of the spot
marked ‘D1’, making sure that the silver band on the diode is facing the bottom edge of the board
(Figure 4).
Insert the diode leads such that silver stripe is
facing the bottom edge of the board (like the
stripe painted on the board). Pull the diode all
the way through so that it sits flush against the
board. This diode is only half-way in.
Figure 4. Placement of the black and silver diode on the PCB
Pull the diode leads through the holes until the diode sits securely on top of the spot marked ‘D1’.
Attach a heat sink onto the diode’s lead on the front side of the board to protect the diode from
overheating during soldering. Solder the leads on the backside of the board (Figure 5).
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Solder mounts
Figure 5. The backside of the PCB after the orange and black Zener and black and silver diode have
been soldered onto it
Diodes flush against
the PCB
Figure 6. The front side of the PCB after the black and silver diode and the orange and black Zener
diode have been soldered onto it
Step 3
Identify the striped resistor, which is to be placed over the spot marked ‘R1’ on the PCB. Bend the leads
and insert them into the holes on either ends of the spot marked ‘R1’ and solder the leads on the
backside of the PCB, following the soldering instructions given above.
Identify the white capacitor, which is to be placed over the spot marked ‘C1’ on the PCB. Bend the leads
and insert them into the holes on either ends of the spot marked ‘C1’ and solder the leads on the
backside of the PCB, following the soldering instructions given above. Note that the black strip is
orientated up (as shown in the figure).
5
Figure 7. The front side of the PCB with the striped resistor, white capacitor, orange and black Zener
and black and silver diode installed. Note the orientation of the stripe on the white capacitor.
Step 5
Identify the two red light emitting diodes (red LEDs), which are to be placed over the spots marked ‘E1’
and ‘E2’ on the PCB. Insert the leads of one of the red LEDs into the spot marked ‘E1’ so that the red
LED faces out over the bottom edge of the board. The holes for the LED leads are wide enough so that
only the bottom portion of the lead pulls through to the PCB. The LED should not lean forward or back,
but should be straight up and down (Figure 8).
Figure 8. Placement of the red LED on the PCB
Solder the leads on the backside of the PCB, following the soldering instructions given above. Repeat for
the second LED placed in the spot for ‘E2’. The finished board would have all components placed as
given in Figure 9.
6
Figure 9. Front side of the PCB with all electronic components soldered onto it
Step 6
From the wire that is provided, cut a 2.5 inches length wire and strip the insulation ¼” on one end and
¾” on the other end (Figure 10). Insert the ¼” stripped end through the hole on the PCB marked ‘Lid’
and solder on the backside of the PCB. Cut any extra strands of wire.
Figure 10. A 2.5-inch wire that is stripped on both ends. This photo is not necessarily to scale. Use a
ruler to be sure.
Step 7
Similarly, cut a 2-inch piece of wire (note that the wire is ½” shorter than the previous wire) and strip the
insulation ¼” on one end and ¾” on the other end. If you are using a hand tool for stripping, the wire is
20 AWG. Insert the ¼” stripped end of this wire through the hole on the PCB marked ‘Base’ and solder
on the backside of the PCB. Cut any extra strands of wire. Figure 11 shows the backside of the board
after all the soldering is completed.
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Figure 11. Backside of the completed PCB
Step 8
Working with your teacher or teaching assistant, test your board. The procedure is briefly described
here. Your teacher will have more details.
Using the circuit tester, connect one end of the tester lead to the white capacitor lead facing the top
edge of the PCB. When touching the other tester lead to the other side of the capacitor on the circuit,
both of the red LEDs should light up (Figure 12).
Red lead from the
circuit tester
Black lead from the
Both red LEDs circuit tester
are lit
Figure 12. Both red LEDs light up when connected to the circuit tester across the white capacitor
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Complete the testing by connecting the circuit tester diodes to the tester leads. Touch the red wire to
the white capacitor lead near the top edge of the PCB and the black wire to the negative side of the
capacitor (nearest the LED’s). Now, only one of the LEDs should light up (Figures 13, 14).
One lit red
LED
Figure 13. Connections for the second testing of the circuit
If the LEDs do not light in the first and second test as described, the circuit is faulty and needs to be
troubleshot for incorrect component placement, loose connections, and faulty soldering.
Step 9
Remove the plastic paper from one side of the adhesive pad. Stick it onto the inside bottom of the box
centered under the two holes, on the side closest to the drilled holes (Figure 15).
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Figure 15. Placement of the adhesive pas inside the box
Step 10
Remove the plastic paper from the top side of the adhesive pad. Place the PCB on the top side of the
adhesive pad, ensuring that the two LEDs are placed in the holes on the side (Figure 16). Press firmly to
assure that that PCB sticks to the adhesive, which keeps it attached to the inside bottom of the box
(Figure 17).
Figure 16. Placement of the LEDs on the PCB in the holes on the box
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Figure 17. Placement of the PCB inside the box
Step 11
Insert the white wire coming out of the PCB ‘Base’ into the hole on the bottom surface of the box
(Figure 18).
Figure 18. Placing the base lead through the hole on the bottom surface of the box
Pull the wire through to the outside, spread the strands, and bend them onto the outside surface of the
box (Figure 19).
11
Figure 19. The stranded wires of the base wire bent onto the outside bottom surface of the box
Cut a 3-inch piece of the copper foil, remove the plastic paper, and place on top of the bent strands of
wire (Figure 20).
Figure 20. Placing the foil over the stranded wire
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Step 12
Similarly, insert the white wire coming out of the PCB ‘Lid’ into the hole on the lid of the box (Figure 21).
You’ll need to have the lid very close to the box when you complete this step. Don’t try using longer
wires, as the circuit will be destroyed by when the longer lid wire comes close the base wire, and the
thousands of volts of a defibrillation pulse is applied.
Hole on lid for
the wire
Figure 21. Placing the lid wire through the hole on the lid of the box
Pull the wire through to the outside, spread the strands, and bend them onto the outside surface of the
box. Cut a 3-inch piece of the copper foil, remove the paper, and place on top of the bent strands of
wire (Figure 22).
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Figure 22. The landing pad on the lid of the box
Figure 23. PCB with completed wiring
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Step 13
Please cut out the labels shown below. You may, if you wish complete the S/N field. Your serial number
is your initials (optional) followed by a club code your club leader assigned, followed by your zip code
(where the club met to assemble the devices) followed by the eight digit date. So for example, if your
name is John Robert Doe and your club code is AVS and you built your device in zip code 10001 on the
4th of February, 2001, then your serial number is: JRDAVS1000102042001.
Engineering World Health
Defibrillator Tester v3.0
www.ewh.org
Model DF30
S/N: .. .. .. .. .. .. .. .. .. .. .. .. .. ..
The labels should be applied on the sides of the device.
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Final Testing:
Close the lid and screw the lid onto the box. Shake the box lightly to verify that there are no loose
components. If there are loose components, open the box, verify that all soldered connections are
intact. Re-apply solder, if need be. Test the board again using the circuit tester as described above. If
there are no loose components and the circuit passes the tests, place the lid on again and screw it to the
box base. The kit is now complete.
Send completed kits to Engineering World Health at
311 S. Highland, #289
Memphis, TN 38111
We’ll send this kit to a needy hospital in the developing world. If you include a check for $15, we’ll also
send a kit to a school or club that can’t afford to purchase these kits.
By completing this kit, you’ve helped save countless lives in the developing world.
Would you like to learn more: visit Engineering World Health at www.ewh.org
Circuit Tester Construction Manual
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Necessary Parts:
2-battery holder with leads (1)
AA batteries (2)
Diodes (2)
Building the Circuit Tester
The circuit tester is used to verify that the PCB is working properly after its construction. Two batteries
and a battery holder are used for this purpose. The two batteries in series will provide 3V, which is
sufficient to light up both the LEDs on the circuit board, if the PCB is functioning properly (Figure 1).
Lit
LED
s
Figure 1. Two lit LEDs when the circuit is completed
However, in order to light up only one of the LEDs between 2.6V and 3V is needed. In order to achieve
this voltage drop, solder the two tester diodes in series (Figure 2). Solder the left end of the diodes-in-
series to the red lead from the battery holder such that the striped side is used to make contact with the
capacitor lead (Figure 3).
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Stripe is Soldered Stripe is
towards the leads towards the
right side right side
Figure 2. Two soldered diodes
Soldering point for the
diodes to the red lead
from the battery
holder
Striped end of the
diode touches the
capacitor
1 lit LED
Figure 3. One lit LED when the circuit is completed through a series of two diodes
Test Procedure:
1. Place two AA batteries in the battery holder.
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2. Touch the capacitor lead closer to the top edge of the board (where the large striped resistor is
found) with the red lead from the battery holder and the capacitor lead closer to the bottom
edge of the board with the black lead from the battery holder (Figure 4).
Figure 4. Schematic of tester circuit
3. Both LEDs should light up as in Figure 1. If they do not, please troubleshoot for poor
connections and bad components.
4. Touch the free end of the diodes-in-series (soldered to the red lead from the battery holder) to
the capacitor lead closer to the top edge of the board.
Figure 5. Schematic of tester circuit
Touch the black lead from the battery holder to the capacitor lead closer to the bottom edge of
the board (Figure 4). The E1 LED should light up. If it does not, please troubleshoot for poor
connections (solder joints missing or incomplete) and bad component placement (not in right
spaces or in the right orientation).
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Point where the diodes-
in-series touch the top
capacitor lead
Point where the black
Red lead
wire touches the bottom
capacitor lead
E1 is lit
Black lead
Figure 6. Placement of the battery holder leads
The circuit tester is now ready to be used.
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