Assemble the Circuit

OK, you're almost through! Be sure to follow each of the remaining steps carefully to avoid errors.

1. Find these wires which you previously prepared:
   7 cm red and 9 cm black
2. Form a u-shaped hook in the exposed 12-15 mm end of each wire as you did when preparing the switch.
3. Loosen the end hex nuts on the two terminal posts that protrude inside the VHS case.
4. Place the u-shaped hook of the red wire over the terminal of the red post and use pliers to tighten the nut over the wire. The bend in the hook should be oriented in the same direction the nut is tightened (clockwise).
5. Place the u-shaped hook of the black wire the terminal of the black post as described in the previous step. Use pliers to tighten the nut over the wire.
6. Notice that the holes in the breadboard are coded. Rows are designated by letters of the alphabet. Columns are designated by numbers. This means we can label any hole in the breadboard with a letter and a number. Install the 741 operational amplifier integrated circuit (IC) in the breadboard as shown in Fig. 4. Pin 1 of the 741 should be installed at position F1 in the breadboard. Gently push down of the IC until its pins are firmly inserted in their holes. Make sure all 8 pins are properly inserted. If a pin bends and does not install, gently remove the IC, use pliers to straighten the pin and try again.
7. Use a pencil or marker pen to mark the LED leads at points 13 mm from the LED body.
8. Notice that one side of the lower end of the LED has a flat place as shown in Fig. 1 and Fig. 4. Hold the leads of the LED with pliers so that the side of the pliers away from the LED body is along the marked points on the leads. Orient the LED so that the flat space is nearest you and bend the leads at a right angle.
9. Insert the end of the LED through the upper hole in the angle bracket adjacent to the breadboard while also inserting its leads in holes J2 and J3. Be sure the lead closest to the flat space on the LED is inserted in hole J2. Press the back of the LED flush against the angle bracket.
10. Insert a black connection wire between holes G3 and X1.
11. Insert the 2 wire leads of the resistor in holes H2 and D3.
12. Insert the red wire from the red output terminal in hole A3.
13. Insert the black wire from the black output terminal in hole X5.
14. Remove the outer retaining hex nut and switch plate from the switch, align the switch so that the 2 terminals without wires face the 2 terminals installed in the rigid side of the case, and install the switch in the hole in the bottom of the case. Replace the hex nut (but not the switch plate) over the switch and tighten with pliers.
15. Insert the center black switch lead in hole G4.
16. Insert the center red switch lead in hole B2.
17. The exposed copper leads from the 9-volt battery connecter wires are thin and by themselves will not necessarily stay inserted into holes in the breadboard. So follow this method: Insert the black lead from a 9-volt battery connector half way into hole E23. Then force the black lead from the lower left side of the switch into the same hole.
18. Find the red connection wire you prepared. Insert the red lead from the same 9-volt battery connector half way into hole X19. Then force one end of the red connection wire into the same hole. IMPORTANT: Make sure the wire you have just installed is from the same battery connector!
19. Insert the black lead from the second 9-volt battery connector half way into hole X11. Then force the second end of the red connection wire (the first end of which you previously inserted into hole X19) into the same hole (X11).
20. Insert the red lead from the second 9-volt battery connector half way into hole F23. Then force the red lead from the left side of the switch into the same hole.
21. Now set the TERC VHS-1 aside and take a break before going further.