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SubSystem : IP3

Task Title:
L.E.D. Control
Name: Switch Triggers
(- going)


OnTrack
equipment you will need:

IP3, OP1 Modules
Bridge Power Base
Component Card
2 x 2mm White Leads
2 x Crocodile Leads
Multimeter


Connecting Subsystems:

1, Place the IP3 and OP1 modules onto the Bridge Power Base
(Fig 3.2). Connect up the "OnTrack" module to hold these down.

2, Use two white leads (shown black in diagram) to connect module OP1 to the Light Emitting Diode (L.E.D.)

3, Connect the two crocodile leads, as shown, to the multimeter. You will need to "stack" the middle connection to the white plug placed earlier.

4, Turn the multimeter switch to the 20v (D.C.) position.

5, Check your wiring is accurate and then connect the 9 volt power supply.

Testing and Investigating:

Don't forget to write up your method and results afterwards.

6, Press and hold down the switch to make the circuit - the L.E.D. should light. If it doesn't, you may need to check that the leads have been connected the right way round.

7, With your finger still on the switch, what voltage or potential difference is being measured by the meter? You have just measured the voltage between the negative side of the power supply and the output of the I/P3 module. So write down the voltage at the output of I/P3?

8, Now release your finger from the switch and look to see if the meter reading changes. What has happened to the L.E.D.?

9, Looking back at the circuit diagram and description on the previous page, describe in your own words why the pull- up resistor and switch affect the meter reading.

 

 

Connecting up further circuits

10, Remove all the leads from the O/P I module and connect the L.E.D. to the bottom negative socket and to the middle connection.

11, Repeat the above test - pressing and releasing the switch. Note what happens to the L.E.D. now. Is this what you would expect? What component is affecting its brightness?