CS 240 Lab 1

Learning Goals & Reflection

CS 240 Lab 1

• Lab slides
• Lab notebook

Learning Goals

Note: Each lab will have a learning goals page like this one. At the end of lab, you’ll be asked to fill out a Google form to reflect on your learning in each category.

Core Goals

Students can:

1. Use basic electronic concepts:
   1. Memorize Ohm’s law and explain what current, voltage, and resistance are at a high level in terms of electricity.
   2. Explain the dangers of electric shock, and how current, voltage, and resistance contribute to electric danger/safety.
   3. Explain what a “short circuit” is and why is is usually undesirable.
   4. Explain the basic components necessary to form a “closed circuit” and what an “open circuit” is in contrast.
2. Read circuit diagrams and truth tables:
   1. Recognize the circuit diagram symbols for resistors, transistors, voltage sources, and ground connections
   2. Explain how connected vs. disconnected crossing points are indicated in a circuit diagram.
   3. Explain what letter labels in a circuit diagram mean.
   4. Identify the output of a circuit for certain inputs based on a truth table.
   5. Analyze a circuit diagram piece-by-piece to figure out the voltage level and current availability at each point in the circuit, given known input voltages.
   6. Analyze the operation of a circuit for all possible input high/low voltage combinations to build a truth table for each output.
   7. Analyze the operation of a circuit abstracted over unknown input voltages to describe the overall operation of the circuit in terms of abstract inputs.
   8. Recognize the circuit diagram symbols for NOT, AND, and OR gates.
   9. Recognize the circuit diagram symbols for NAND and NOR gates.
3. Build and explain basic transistor circuits:
   1. Identify voltage and ground sources and trace how these are connected on a protoboard.
   2. Explain how rails are connected horizontally and vertically inside a protoboard.
   3. Cut and strip plastic-shielded wire.
   4. Plug wires into a protoboard to make connections to components that are already mounted.
   5. Identify resistors, transistors, LEDs, and integrated circuits, both as physical components and on circuit diagrams.
   6. Explain how to connect to the push-button input, logic switch input, and logic indicator output sections of our prototyping stations.
   7. Explain what will happen if you create a transistor circuit without including any resistors.
   8. Wire a transistor with a push-button input to serve as a NOT gate controlling a logic indicator LED, given a diagram of the circuit.
   9. Wire two transistors in parallel to create a circuit which implements a NOR gate, given a diagram of the circuit.
   10. Explain how transistors can be used to create a circuit for a NOT gate, and the operation of the circuit in terms of where current flows and why in each possible input configuration.
4. Work with integrated circuits:
   1. Read model numbers on integrated circuits and look up their wiring diagrams.
   2. Use the notch to identify the “top” of an IC, and “count around” the IC to identify each input/output pin on a physical IC based on a wiring diagram.
   3. Identify power and ground inputs from an IC’s wiring diagram and connect these to the +5V and ground lines on a prototyping station.
   4. Use a 7408 AND gate IC along with built-in switches and LEDs to create a circuit that requires two switches to be turned on at once in order to light up an LED.
   5. Test the outputs of a circuit built on a prototyping station to fill in a truth table for that circuit.
5. Work with Boolean algebra notation:
   1. Explain how AND, OR, and NOT are represented in Boolean algebra notation.
   2. Explain the input/output relationships for a Boolean algebra function in plain language.
   3. Draw a circuit diagram involving basic gates to represent a Boolean algebra function, correctly labeling input and output wires.

Stretch goals

1. Build and explain basic transistor circuits:
   1. Explain how transistors can be used to create a circuit for a NOR gate, and the operation of the circuit in terms of where current flows and why in each possible input configuration.
   2. Explain the difference (or lack thereof) between inputs and outputs in a circuit.
   3. For each basic gate (NOT, AND, OR, NAND, and NOR), explain how it can be constructed using transistors.
2. Work with integrated circuits:
   1. Use 7408 AND gate and 7432 OR gate ICs along with built-in switches and LEDs to create a circuit that implements the Boolean function $F = AB + BC$, where $F$ is a logic indicator output and $A$, $B$, and $C$ are logic switch inputs.
3. Work with Boolean algebra notation:
   1. Write a Boolean algebra function which gives the output of a circuit show in a circuit diagram.

Reflection

Fill out the CS 240 Lab 1 Reflection form to complete today’s lab reflection.