During this first lab session, you challenge will be to assemble a series of electical components into a working circuit. Carefully follow the outlined sequence of steps.

The mystery circuit has been broken down into functional blocks and will be breadboarded in a sequence of steps. Each step involves the assembly of several components and connections that perform a specific function. These sub-circuits wll be analysed fully as the material is covered in the lectures. As you proceed with the assembly, match the location of the components on your breadboard to that shown in the pictures. This will make it easier to spot incorrectly placed components.

Note also that the pin numbering scheme on your breadboard may differ from that shown in the pictures.

To make the experience of assembling a working circuit more enjoyable:

1. Be sure that the DC power to the breadboard is initially OFF;
2. verify by direct measurement the values of all the resistors and capacitors with the component tester;
3. verify that the jumper wires used are not broken (test for ~0 Ω resistance with the component tester);
4. assemble the circuit in a systematic and organized fashion;
5. verify that your assembled circuit connections correspond to those of the schematic diagram.

As you assemble your mystery circuit, create a schematic diagram that identifies the various connections between the circuit components. You need not know the function of the integrated circuit (IC) "chips" or the transistors. Treat them as "black boxes" and use the pin numbers to identify their connection to the rest of the circuit.

On a sheet of paper or tablet, try to reproduce the physical circuit being assembled. Begin by sketching the power lines, labeling these "+5 V" and "0 V" or "GND". Add components and their connections to your drawing as you assemble the mystery circuit, taking care to:

• identify resistors and capacitors with their appropriate electrical symbol, the reference label and nominal value given in the assembly steps. Verify that you have selected the correct component by measuring it with the component tester and tabulate the value. It will be needed during future lab sessions;
• identify light-emitting diodes (LEDs) with the symbol correctly oriented and transistors with their correct pinout (legs are E(mitter), B(ase) or C(ollector)) and type symbol (NPN or PNP), as given by the component tester;
• observe the convention of IC chip pin numbering as described in the assembly steps.

Once you have a sketch of the circuit, you can clarify the schematic with some simple edits. For example, rearrange the IC pin labels so that the ground and power connections are close to the respective power rails and and rearrange the wiring to minimize the number of connection cross-overs. The trick is to be organized and systematic in your component layout; this will make the circuit schematic easier to follow and the circuit operation easier to understand.

Here are some useful links to circuit schematic symbols and resistor colour codes

Lab book entry

• a short summary of your circuit assembly experience;
• an outline of any issues that you encountered with a description of how they were resolved;
• a clear picture of your completed mystery circuit;
• a picture of the initial and final version of your schematic diagram;
• a table identifying the various R,C components with their nominal and measured values.