Drawing wires, junctions and crossings neatly

Name:

Date:

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Quick Questions

Shade in the A or B circle for each question.

1. Two wires cross on a circuit diagram and there is a dot where they cross. What does this mean?

A The wires are connected

B The wires are not connected

2. Two wires cross and there is NO dot where they cross. What does this mean?

A The wires are connected

B The wires are not connected

3. Input A must feed both an AND gate and a NOT gate. Which is the correct way to draw it?

A Draw one wire from A and put a junction dot where it splits to both gates

B Draw one wire from A that crosses the other wire with no dot

4. Where should the inputs A, B and C be drawn on a neat logic circuit?

A On the right, with the output X on the left

B On the left, with the output X on the right

5. Which is the better way to draw a wire in an exam circuit?

A Straight lines, drawn neatly with a ruler

B Curved, wavy lines that loop around the gates

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1A solid dot where two wires meet		AA, B, C ---> [gates] ---> X
2Two wires cross with no dot		BThe wires are not connected and carry separate signals
3Inputs are drawn on the left and the output on the right		CA -o-- NOT gate \| +-- AND gate
4One input can feed two gates by splitting its wire at a junction dot		DThe dot wrongly joins A and B, so they would share one signal. If the wires are not connected, they must cross with no dot.
5Wire from A crosses wire from B with a dot at the crossing, but the wires should be separate		EThere is no junction dot, so it looks like a crossing and the split is unclear. A dot is needed where one wire splits to two gates.
6Input A feeds two gates, but the wire splits with no dot		FThe wires are connected, so input A feeds both gates

Definitions

junction dot

Fill in the Blanks

Complete each line of code by filling in the missing parts.

X = (A AND B) OR (_ AND C) # A feeds two gates: dot on wire A

A crosses B, no ___ -> not connected

inputs: A, B on the left output: X on the _____

junction on A: one input, ___ gates

label inputs A, B, C and output _

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A Inputs A and B on the left

B Output X on the left

C Wires run straight and level

Question 2

A A feeds an AND and an OR gate

B Draw no dot where A splits

C Both branches run to gates

Question 3

A Wire A crosses wire B

B They are not joined

C Keep the wires straight

D Draw a dot where they cross

Question 4

A A feeds a NOT gate

B A also feeds an AND gate

C Dot goes after the AND gate

Question 5

A Label the inputs and output

B Write A, B, C at the right end

C Write X at the output wire

Answer Key

Drawing wires, junctions and crossings neatly

Section A: Quick Questions

A — The wires are connected

B — The wires are not connected

A — Draw one wire from A and put a junction dot where it splits to both gates

B — On the left, with the output X on the right

A — Straight lines, drawn neatly with a ruler

Section B: Match the Pairs

A solid dot where two wires meet → The wires are connected, so input A feeds both gates

Two wires cross with no dot → The wires are not connected and carry separate signals

Inputs are drawn on the left and the output on the right → A, B, C ---> [gates] ---> X

One input can feed two gates by splitting its wire at a junction dot → A -o-- NOT gate | +-- AND gate

Wire from A crosses wire from B with a dot at the crossing, but the wires should be separate → The dot wrongly joins A and B, so they would share one signal. If the wires are not connected, they must cross with no dot.

Input A feeds two gates, but the wire splits with no dot → There is no junction dot, so it looks like a crossing and the split is unclear. A dot is needed where one wire splits to two gates.

Section C: Definitions

junction dot — A dot drawn where wires join, so one input can feed two gates. Wires that cross with no dot are not connected. Draw inputs on the left and the output on the right.

Section D: Fill in the Blanks

X = (A AND B) OR (A AND C)
# A feeds two gates: dot on wire A

A crosses B, no dot -> not connected

inputs: A, B on the left
output: X on the right

junction on A: one input, two gates

label inputs A, B, C and output X

Section E: Spot the Error

B — The output must be drawn on the right of the circuit. It should read 'Output X on the right'.

B — When one input feeds two gates, a junction dot must be drawn where the wire splits. It should read 'Draw a dot where A splits'.

D — Wires that cross but are not connected must have no dot. A dot would wrongly show they are joined.

C — The junction dot goes at the point where the input wire splits, before the gates. It should read 'Dot goes where A splits'.

B — Input labels A, B and C go at the left end of the input wires. The right side is for the output X.